Updated October 15, 2026

    The glossaryspeak fly fishing.

    The words you'll hear at the fly shop and on the water, from BWOs to tailwaters, in plain English.

    A

    Abdomen
    The posterior section of an insect's body, containing most of the digestive and reproductive organs.
    Adult
    The fully developed, winged reproductive stage of an insect's life cycle, often seen flying or on the water's surface.
    Alberto Knot
    A strong and slim knot used for joining two lines of different diameters, especially monofilament to fluorocarbon.
    American Eels
    Catadromous fish known for their snake-like bodies, which migrate from freshwater to the Sargasso Sea to spawn.
    Anadromous
    Describes fish that migrate from saltwater to freshwater to spawn, such as salmon and steelhead.
    Antennae
    Sensory appendages on an insect's head, used for touch, smell, and taste.
    Aquatic Insects
    Insects that spend all or part of their life cycle in water, forming a primary food source for many fish species.
    Arbor
    The central axis of a fly reel around which line is wound.

    B

    Back Eddy
    An eddy that forms on the downstream side of an obstruction, where water flows upstream against the main current.
    Backing
    Thin braided line attached to the reel beneath the fly line, providing extra length for fighting large fish.
    Bank
    The land alongside a river, stream, or lake, providing cover and habitat for fish and insects.
    Blood Knot
    A traditional and very strong knot used for joining two lines of similar diameter, especially for leader construction.
    Blue Catfish
    A large freshwater catfish species, often found in deep river channels and reservoirs, known for its powerful fight.
    Brook Trout
    A beautiful native trout species, often found in cold, clear streams and known for its vibrant colors.
    Brown Trout
    A highly sought-after trout species known for its elusive nature and often large size.
    Butt Section
    The thickest, bottom-most section of a multi-piece fly rod, providing leverage and power.
    BWO
    Blue-Winged Olive — a common mayfly genus (Baetis) important in fly fishing.

    C

    Caddis
    An order of aquatic insects (Trichoptera) that are a primary food source for trout.
    Catadromous
    Describes fish that migrate from freshwater to saltwater to spawn, such as American eels.
    Channel
    The deepest and fastest-flowing part of a river or stream.
    Channel Catfish
    A popular freshwater game fish known for its distinctive barbels and strong fighting ability.
    Chinook Salmon
    The largest species of salmon, highly prized for its size and strength.
    Clinch Knot
    A common and reliable knot used to attach a fly to a tippet.
    Confluence
    The point where two or more rivers or streams meet and combine their flows.
    Crappie
    A panfish species popular for its delicate meat and often found in schools around submerged structure.
    Crayfish
    A common freshwater crustacean that is a significant food source for many game fish.
    Creek
    A small stream or river, often characterized by intimate fishing experiences.
    Cruising
    Describes fish that are actively swimming and searching for food rather than holding in a stationary position.
    Current
    The continuous, directed movement of water in a river or stream, which influences fish behavior and fly presentation.
    Curve Cast
    A casting technique designed to make the fly land on the water in a curve, allowing the fly to drift naturally before the line straightens.

    D

    Dead Drift
    A presentation where the fly floats naturally with the current, without drag from the line.
    Deep Water
    Areas of a river or lake with significant depth, often providing refuge for fish during bright conditions or low flows.
    Double Haul
    An advanced casting technique that increases line speed and distance by pulling the line with the non-casting hand during the cast.
    Drag
    Unnatural movement of a fly caused by current pulling on the line or leader.
    Drop-off
    A sudden increase in water depth, often a prime location for fish to ambush prey.
    Dropper
    A second fly tied off the bend or eye of the lead fly, creating a multi-fly rig.
    Dry Fly
    A fly pattern designed to float on the surface of the water, imitating an adult insect.
    Dubbing
    Natural or synthetic fibers twisted onto thread to form the body of a fly.
    Dun
    The subimago stage of a mayfly, characterized by dull wings and a short flight, which emerges from the water and flies to vegetation to molt.

    E

    Eddy
    A circular current of water, often found behind an obstruction or in a bend of a river, where water flows in the opposite direction of the main current.
    Emergence
    The process by which an aquatic insect transforms from its larval or pupal stage and rises to the water's surface to become an adult.
    Emerger
    An aquatic insect transitioning from nymph to adult at or just below the water surface.
    Estuary
    A partially enclosed coastal body of brackish water where freshwater from rivers and streams mixes with saltwater from the ocean.
    Euro Nymphing
    A tight-line nymphing technique using long leaders and no indicator for precise contact with the fly.
    Exoskeleton
    The rigid outer covering of an insect, which is shed during molting as the insect grows.

    F

    Fall Flow
    The typical water levels and current speeds observed in a river during the autumn season.
    Fallfish
    A common minnow species found in eastern North American streams, often targeted by fly anglers.
    False Cast
    Casting the line back and forth in the air without letting it touch the water.
    Feeding Lane
    A specific path or area in a river or lake where fish position themselves to intercept drifting food items.
    Feeding Lie
    A specific location in the water where a fish positions itself to actively feed on passing prey.
    Ferrule
    The joint where two sections of a multi-piece fly rod connect.
    Figure Eight Knot
    A stopper knot that can also be used to create a loop, known for its reliability and ease of untying.
    Fishing Vest
    A garment with multiple pockets designed to hold and organize an angler's essential gear and accessories.
    Flat
    A relatively shallow, wide, and slow-moving section of a river or stream, often with a uniform bottom.
    Flathead Catfish
    A large, predatory freshwater fish characterized by its broad, flattened head, often found in slow-moving rivers.
    Floatant
    A substance applied to dry flies or leaders to make them float higher on the water's surface.
    Flow Profile
    The measurement and description of water volume and velocity in a river or stream over time.
    Fly
    A general term for the artificial lure used in fly fishing, designed to imitate aquatic or terrestrial insects and baitfish.
    Fly Box
    A container used to store and organize an angler's collection of flies.
    Fly Line
    The weighted line that provides the mass needed to cast a fly, available in various tapers and densities.
    Fly Reel
    A simple reel used to store fly line and provide drag when fighting a fish.
    Fly Rod
    The specialized rod used in fly fishing, designed to cast the weight of the fly line rather than the fly itself.
    Fly Tying Materials
    Various natural and synthetic components, such as feathers, fur, and thread, used to construct artificial flies.
    Fly Tying Vise
    A specialized tool used to securely hold a hook while an angler attaches various materials to create an artificial fly.
    Forceps
    Small, scissor-like tools used by anglers for crimping barbs, removing hooks from fish, or handling small flies.
    Freestone
    A river or stream fed primarily by surface runoff and precipitation rather than springs.
    Fry
    A very young fish, typically recently hatched, that is still developing and feeding on its yolk sac or small organisms.

    G

    Gills
    Respiratory organs found on some aquatic insect larvae and nymphs, allowing them to extract oxygen from water.
    Golden Shiners
    A common baitfish species that can be imitated by small streamer patterns.
    Grayling
    A distinctive cold-water fish with a large, sail-like dorsal fin, found in northern regions.

    H

    Hackle
    A feather wound around the hook shank to create legs, movement, or flotation on a fly.
    Hatch
    A period when aquatic insects emerge from the water in large numbers, triggering fish feeding activity.
    Headwater
    The source or upper reaches of a river or stream, typically characterized by cold, clear water.
    Hogchokers
    Small, flat-bodied bottom-dwelling fish found in estuaries and coastal waters, sometimes targeted by fly anglers.
    Holding Lie
    A location in the water where a fish rests, conserves energy, and feels secure, often near cover or a current break.
    Holding Water
    Areas in a river or lake where fish rest and conserve energy, often characterized by moderate depth, current, and nearby cover.

    I

    Imago
    The final, sexually mature adult stage of an insect, particularly referring to the spinner stage of a mayfly.
    Improved Clinch Knot
    A strong and reliable knot used to attach a fly to the tippet or leader.
    Indicator
    A buoyant device attached to the leader to detect strikes when nymphing.
    Instar
    A developmental stage of an insect between two molts, particularly used to describe the growth stages of nymphs and larvae.

    L

    Lake
    A large body of still water, often fished for trout, bass, and other species.
    Landing Net
    A net used to safely scoop and secure a fish once it has been reeled in close, minimizing stress and handling time.
    Largemouth Bass
    A popular warm-water game fish known for its aggressive strikes and large mouth.
    Larva
    The immature, worm-like stage of an insect's life cycle, often found clinging to rocks or vegetation.
    Leader
    The tapered monofilament or fluorocarbon section connecting the fly line to the tippet and fly.
    Line Dressing
    A substance applied to fly lines to improve their floating or sinking characteristics and reduce friction.
    Log Jam
    An accumulation of logs, branches, and debris in a river or stream, providing significant cover and structure for fish.
    Loop Knot
    A type of knot used to create a non-slip loop at the end of a line, allowing a fly to move more freely.

    M

    Match the Hatch
    Selecting a fly pattern that closely imitates the insects currently hatching on the water.
    Mayfly
    An aquatic insect whose various life stages (nymph, emerger, dun, spinner) are crucial food sources for fish.
    Mend
    Repositioning the fly line on the water after casting to control drift speed and reduce drag.
    Midge
    Tiny two-winged flies (Chironomidae) that are a year-round food source for trout, especially in winter.
    Molting
    The process by which an insect sheds its exoskeleton to grow, occurring multiple times during its life cycle.
    Mouth
    The point where a river or stream empties into a larger body of water, such as a lake, another river, or the ocean.

    N

    Nail Knot
    A knot used to attach fly line to backing or a leader butt to fly line, often requiring a special tool or 'nail' to tie.
    Nippers
    Small, sharp tools used to cleanly cut monofilament or fluorocarbon fishing line.
    Non-Slip Mono Loop
    A specific knot that forms a strong, non-cinching loop, ideal for attaching flies to a leader.
    Nymph
    The underwater larval stage of an aquatic insect; also a fly pattern imitating this stage.
    Nymphing
    A fly fishing technique that involves presenting a weighted fly (nymph) subsurface to imitate aquatic insect larvae and pupae.

    O

    Obstruction
    Any object in the water, such as a rock, log, or submerged branch, that disrupts current and provides cover for fish.
    Overhead Cast
    The fundamental fly casting motion involving a backcast and a forward cast, used to propel the fly line and fly through the air.

    P

    Parachute Cast
    A specialized cast used to land a dry fly softly and precisely, often by stopping the rod high to allow the leader to collapse.
    Parr
    A juvenile salmon or trout that exhibits distinctive vertical bars (parr marks) on its sides, indicating it is still in its freshwater stage.
    Peak Seasons
    The optimal times of the year for fly fishing in a particular location, often coinciding with prolific hatches or fish migrations.
    Perfection Loop
    A strong, non-slip loop knot often used to create a loop at the end of a leader or for attaching leaders to fly lines.
    Pile Cast
    A casting technique where the fly line is intentionally piled up on the water, creating slack for a longer, drag-free drift.
    PMD
    Pale Morning Dun — a prolific mayfly hatch (Ephemerella) important for summer dry fly fishing.
    Pocket Water
    Sections of a river characterized by small, turbulent currents and eddies around rocks, offering prime feeding lies.
    Pool
    A deeper, slower-moving section of a river or stream, often providing holding lies for fish.
    Presentation
    The manner in which a fly is cast and delivered to the fish.
    Pupa
    The non-feeding, transitional stage in the life cycle of some insects, such as caddisflies, before emerging as adults.
    Pupal Shuck
    The discarded outer casing of an insect after it has transformed from the pupal stage to the adult stage.

    R

    Rainbow Trout
    A popular game fish known for its vibrant colors and acrobatic fights.
    Rapids
    A section of a river where the water flows quickly over obstacles, creating turbulent and aerated water.
    Reach Cast
    A casting technique where the angler extends the rod arm upstream or downstream during the cast to achieve a longer drag-free drift.
    Redd
    A shallow, gravel-bottomed depression created by female salmonid fish for depositing their eggs.
    Reel Drag
    A mechanical system within a fly reel that applies resistance to the outgoing line, helping to tire and control a fish.
    Reel Seat
    The part of the fly rod where the reel is attached and secured.
    Reel Size
    The physical dimensions and line capacity of a fly reel, chosen to balance with the rod weight and intended fishing conditions.
    Riffle
    A shallow section of river with a fast, broken surface created by rocks on the streambed.
    Rise
    The visible disturbance on the water surface when a fish feeds on or near the surface.
    Rise Form
    The specific way a fish breaks the water's surface when feeding, which can indicate the type of insect it is eating.
    River
    A natural flowing watercourse, a primary environment for fly fishing.
    River Character
    The unique physical attributes and flow dynamics of a river, influencing fish habitat and fishing techniques.
    Rod Action
    Describes how much of the fly rod bends when casting, typically categorized as fast, medium, or slow.
    Rod Weight
    A numerical rating (e.g., 5-weight) indicating the ideal fly line weight for a particular rod, corresponding to the size of fish and flies it's designed for.
    Roll Cast
    A casting technique used when there is no room for a backcast, propelling the line forward with a rolling motion.
    Run
    A section of river deeper than a riffle but shallower than a pool, with moderate current.

    S

    S-Cast
    A casting technique that introduces S-curves into the fly line as it lands, providing extra slack for an extended drag-free drift.
    Seam
    The boundary between two currents of different speeds, where fish often hold to ambush food.
    Shallow Water
    Areas of a river or lake with minimal depth, often where fish feed on emerging insects or small baitfish.
    Shooting Line
    The process of releasing extra fly line during the forward cast to achieve greater distance.
    Single Haul
    A casting technique where the angler pulls the fly line with their non-casting hand during the forward cast to increase line speed and distance.
    Slack Water
    Areas of a river or lake where the current is significantly slower or nearly still, often found along banks or behind obstacles.
    Smallmouth Bass
    A hard-fighting freshwater fish often found in rivers and rocky lakes.
    Smolt
    A juvenile salmon or steelhead that has undergone physiological changes to adapt from freshwater to saltwater, preparing for its ocean migration.
    Spawning Run
    The migratory journey of fish from their feeding grounds to their spawning grounds to reproduce.
    Spey Cast
    A family of specialized casts designed for large rivers and windy conditions, often used with two-handed rods.
    Spey Casting
    A family of fly casting techniques originating in Scotland, designed for casting long distances with minimal backcast room, often used with two-handed rods.
    Spinner
    The sexually mature, adult stage of a mayfly (imago) that engages in mating flights and then falls back onto the water to lay eggs.
    Split Shot
    Small, lead or non-toxic weights crimped onto the leader to help sink a fly or nymph to the desired depth.
    Spring Flow
    The increased water volume and velocity in a river during spring, often due to snowmelt or heavy rains.
    Steelhead
    An anadromous rainbow trout that migrates to the ocean and returns to freshwater to spawn.
    Stonefly
    A large aquatic insect whose nymphs and adults are important food sources for trout, especially in colder rivers.
    Streamer
    A large fly pattern that imitates baitfish, leeches, or crayfish, typically fished with an active retrieve.
    Strike Indicator
    A buoyant device attached to the leader to help detect subtle takes when fishing nymphs or other subsurface flies.
    Striped Bass
    A large, migratory saltwater or anadromous fish known for its powerful runs.
    Stripping Basket
    A container worn around the waist or attached to a boat, used to hold stripped fly line and prevent tangles, especially in stillwater or surf fishing.
    Stripping Guide
    The largest guide on a fly rod, located closest to the reel, designed to minimize friction as the line is stripped or cast.
    Structure
    Any physical feature in a body of water, such as rocks, logs, weeds, or drop-offs, that provides cover or feeding opportunities for fish.
    Subimago
    The immature winged stage of a mayfly, commonly known as a dun, which is capable of flight but must molt one more time to become a sexually mature adult.
    Summer Flow
    The typical water conditions of a river during the warmer months, often lower and warmer than spring.
    Surgeon's Knot
    A strong and simple knot used to join two lines of similar or slightly different diameters.
    Surgeon's Loop
    A simple, strong loop knot often used to create dropper tags or attach loops to the end of a leader.
    Switch Cast
    A type of spey cast used when there is no room for a backcast, employing a water-borne anchor to load the rod and propel the line forward.

    T

    Tailwater
    A river section below a dam, often with cold, consistent flows that create premier trout habitat.
    Terrestrial
    A fly pattern that imitates land-dwelling insects such as grasshoppers, ants, or beetles, which fall into the water.
    Terrestrial Insects
    Insects that live on land and may accidentally fall into the water, becoming an opportunistic food source for fish.
    Tessellated Darters
    Small, bottom-dwelling fish that are part of the diet for many trout and bass.
    Thorax
    The middle section of an insect's body, located between the head and abdomen, where wings and legs are attached.
    Tip Section
    The thinnest, uppermost section of a multi-piece fly rod, responsible for sensitivity and delicate presentations.
    Tippet
    The thin, terminal section of the leader to which the fly is tied.
    Tributary
    A stream or river that flows into a larger stream, river, or lake.
    Trico
    Tricorythodes — a tiny mayfly that produces dense morning spinner falls in summer and early fall.
    Triple Surgeon's Knot
    A robust knot used to join two lines of similar diameter, commonly for adding a new section of tippet to a leader.
    Tuck Cast
    A cast designed to make a fly land with the leader piled up, allowing the fly to sink quickly or achieve a drag-free drift in complex currents.

    U

    Undercut Bank
    A riverbank where the water has eroded the soil beneath the surface, creating a sheltered overhang that fish often use for cover.
    Uni Knot
    A versatile knot popular for attaching line to a reel, joining lines, or tying on flies.

    W

    Waders
    Waterproof garments worn by anglers to stand in water while remaining dry.
    Wading Boots
    Specialized footwear worn over waders to provide traction and protection while walking in and around water.
    Wading Staff
    A collapsible or fixed pole used by anglers for stability and safety while wading in rivers and streams.
    Walleye
    A popular freshwater game fish known for its excellent table fare and often caught on flies in certain conditions.
    Weight Forward
    A fly line taper where most of the mass is concentrated in the front 30 feet for easier casting.
    Westslope Cutthroat
    A native trout species of the western United States, identifiable by red slashes under its jaw.
    Wet Fly
    A fly pattern designed to sink and drift subsurface, imitating drowned insects or nymphs.
    White Bass
    A schooling freshwater fish known for its aggressive feeding habits and strong fights.
    White Suckers
    A bottom-feeding fish species that serves as a food source for larger predatory fish.
    Whitefish
    A cold-water fish species, often targeted by fly anglers, especially in western rivers.
    Wings
    Appendages used by adult insects for flight, varying in size and shape depending on the species.
    Winter Flow
    The characteristic water conditions of a river during the colder months, often lower and clearer.

    Y

    Yellowstone Cutthroat
    A subspecies of cutthroat trout native to the Yellowstone River drainage.