Abdomen - posterior section of an insect’s body; located just behind the thorax; typically segmented and large in size relative to other body parts

Adult - the winged stage of aquatic insects; reproductive stage.

Attractor - an impressionistic fly pattern, such as a Royal Wulff, tied with certain fish-enticing characteristics, meant to elicit a strike rather than to realistically imitate an insect.

Baetis - widely distributed genus of mayflies typically found in sizes 16 to 22.

Bass Bug - name used to describe a large number of surface bass flies usually tied with hollow hair (such as deer hair).

Beadhead - term used to describe a fly tied with a bead near the eye of the hook, simulating a head, such as a Beadhead Pheasant Tail. Beads can be brass, nickel, tungsten, or ceramic, and typically add weight to the fly in order to help it sink; however, some beads increase buoyancy.

Belly - middle component of a tapered fly line; located past the tip and front taper, but before the rear taper and running line (see running line, front taper, rear taper, and head).

Caddis - one of the three most important aquatic insects imitated by fly fishers; found around the world in all freshwater habitats; adult resembles a moth when in flight; at rest the wings are folded in a tent shape down the back; the most important aquatic state of the caddis is the pupa, which is its emerging stage (also see larva, pupa and emerger).

Callibaetis - widely distributed genus of mayfly that is commonly found in lakes; often called the “Speckled Wing Dun” because of the speckled markings on the leading edge of the adult’s wings. Callibaetis are usually found in sizes 16 and 18.

Collar - a fly-tying term for a ring of feathers or hair placed immediately behind the head of the fly.

Damselfly - an important stillwater aquatic insect most commonly imitated in the nymphal form; usually hatches in early to mid-summer. Adult looks like a dragonfly, but folds its wings along its back when at rest.

Deer Hair - most commonly used of the hollow hairs for fly tying; used for the Humpy and the Muddler Minnow styles of flies.

Dry Fly - any fly fished upon the surface of the water; usually constructed of non-water-absorbent materials; most commonly used to imitate the adult stage of aquatic insects.

Elk Hair - hair from the body of an elk that is used in many fly patterns to supply bulk for a body or to provide added flotation.

Emerger - pertaining to aquatic insects, the name used to describe that time frame when the nymph reaches the surface and the adult hatches out; the emerging nymph may well be the single most important nymph phase for the fly fishers to imitate.

Hackle - a feather, usually from the neck area of a chicken; can be any color (dyed or natural); hackle quality, such as the stiffness of the individual fibers and amount of web, determines the type of fly tied with the hackle; many hackles are grown specifically for fly tying.

Imitative Flies - flies tied to more closely match specific insects (for instance a BWO Comparadun); imitative flies are most effective in slow-moving, clear water, with finicky trout in fertile streams with large populations of aquatic insects.

Impressionistic Flies - flies tied to loosely suggest a variety of insects or insect families; for instance, a Hare’s Ear nymph in sizes 12-16 can be used as both a mayfly and a caddisfly imitation and in larger sizes as a stonefly imitation; impressionistic flies are usually most effective in medium to fast water, in streams with sparser populations of aquatic insects.

Mayfly - world wide, the most commonly imitated aquatic insect; most dry-fly and nymph patterns imitate this insect; nymph stage of the mayfly lasts approximately one year; adult stages last one to three days; adults have one pair of upright wings, making it look like a small sailboat; commonly found in cold or cool freshwater environments.

Midge - a term properly applied to the small Dipterans that trout feed on; often called gnats; similar to mosquitoes in appearance; midges have two wings that lie in a flat “V” shape over the back when at rest; term sometimes loosely applied (and incorrectly so) when referring to small mayflies.

Nymph - immature form of insects; as fly fishers, we are concerned only with the nymphs of aquatic insects.

Stonefly - very important aquatic insect; nymph lives for one to three years, depending on species; most species hatch out by crawling to the shoreline and emerging from its nymphal case above the surface, thus adults are available to trout only along shoreline and around midstream obstructions; adult has two pair of wings which are folded flat along its back when at rest; stoneflies require a rocky bottomed stream with very good water quality.

Streamer - fly tied to imitate the various species of baitfish upon which game fish feed; usually tied using feathers for the wing, but can be tied with hair and/or feathers; tied in all sizes (see bucktail).

Terrestrial - land-based insects, such as ants or grasshoppers, that are often food for fish.

Wet Fly - (1) any fly fished below the surface of the water; nymphs and streamers are wet flies; (2) a traditional style of fly tied with soft, swept back hackle, and a backward sweeping wing; the forerunner of the nymph and streamer.

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Adipose Fin - a small, rayless fin located between the dorsal and caudal fins of salmonids. The adipose fin of hatchery-raised salmon, steelhead, and trout is often removed to distinguish hatchery fish from wild fish.

Anadromous Fish - migratory fish, such as salmon and steelhead, that live the majority of their lives in salt water before migrating to fresh water in order to spawn.

Arbor Knot - knot used in fly fishing to attach backing to the spool of a fly reel.

Backcast - that portion of any fly cast that extends behind the caster (as in false casting).

Barb - the backward-facing projection cut into a hook near the point to reduce the chances of hooked fish escaping.

Barrel Knot - same as blood knot (see blood knot).

Blood Knot - the most widely used knot for tying two pieces of monofilament with similar diameters together; the best knot for construction of a knotted tapered leader; also called the barrel knot.

Casting Arc - the path that the fly rod follows during a complete cast, usually related to the face of a clock.

Caudal Fin - the tail fin of a fish.

Char - genus of fish related to trout that prefer cold water and are found many places in the world, identified by a dark body with lighter-colored spots and white-tipped pectoral, pelvic, and anal fins; examples of char are brook trout, lake trout, arctic char, Dolly Varden, and bull trout.

Clinch Knot - universally used knot for attaching a hook, lure, swivel, or fly to the leader or line; a slight variation results in the improved clinch knot, which is an even stronger knot for the above uses.

Damping - reducing excess vibrations in the rod blank when unloading the rod during a cast. This causes fewer waves in your fly line resulting in more power and distance for less effort.

Delivery - term used to describe the action of casting a fly to a fish or into a promising-looking area of water; synonymous with presentation.

Dorsal Fin - the fin on the back of a fish, often divided into two or three separate sections.

Double Haul - a cast during which the caster quickly pulls and releases the line on both the back cast and the forward cast, used to create greater line speed, enabling the caster to reach farther or cut through wind.

Eddy - a section of water in a stream found on the edge of a current that is less disturbed than the surrounding water, providing a place for fish to hold and for insects to emerge.

False Cast - standard fly-fishing cast; used to lengthen and shorten line, to change direction, and to dry off the fly; frequently overused. In false casting, the line is kept moving backwards and forwards without being allowed to touch the surface of the water or the ground (see casting arc, back cast, and forward cast).

Fly Casting - standard method of presenting a fly to a target using a fly rod and fly line; involves many different casts (see back cast, forward cast, false cast, roll cast, “S” cast, and shooting line).

Forward Cast - the front portion of the false cast or pick-up and lay-down, and a mirror image of the back cast.

Foul Hook - to hook a fish anywhere but in its mouth.

Haul - a pull on the fly line with the non-casting hand to increase line speed and achieve greater distance.

Hook - the object upon which the fly is tied; can be any size from tiny to huge; made from steel wire, and either bronzed, cadmium coated, or stainless; hook designs are variable; style used depends upon the type of fly being tied.

Knotless Tapered Leader - a fly-fishing leader entirely constructed from a single piece of monofilament. Extrusion or acid immersion is most commonly used to taper the leader.

Knotted Leader - fly-fishing leader constructed by knotting sections of different diameter leader material to each other to make a tapered leader. Most commonly used knots to construct such a leader are blood (or barrel) knot and surgeon’s knot (see blood knot, surgeon’s knot, leader, tapered leader, leader material).

Lateral Line - horizontal line along the sides of fish - clearly marked by coloration in some, nearly invisible in others - that works as a sensory organ, composed of a series of canals that detect pressure variations and vibrations in the water.

Leader - the section of monofilament or fluorocarbon line between the fly line and the fly; usually tapered to deliver the fly softly and away from the fly line (see knotted leader, knotless tapered leader, turn over, and monofilament).

Line Tip - the front part of a fly line where the leader is attached; located before the front taper, but still considered part of the head.

Line Weight - the weight (measured in grains) of the first 30 feet of a fly line, used as a way to standardize fly lines in matching them to fly rods of differing stiffness.

Loading the Rod - phrase used to describe the bend put in the rod by the weight of the line as it travels through the air during the cast.

Loop-to-Loop - quick and easy connection system typically used to attach a fly line to a leader by making a loop at the end of the leader (perfection loop knot), pulling the fly-line loop through the leader loop, then pulling the entire leader back through the loop attached to the end of the fly line.

Nail Knot - method used to attach a leader or butt section of monofilament to the fly line, and of attaching the backing to the fly line; most commonly tied using a small diameter tube rather than a nail.

Narrow Loop - term that describes what the fly line should look like as it travels through the air; a narrow loop can best be described as the letter “U” turned on its side; it is formed by using a narrow casting arc.

Needle Nail Knot - same as the nail knot except that the leader or backing is run up through the center of the fly line for 3/16 to 3/8 inch, then out through the side of the fly line before the nail knot is tied; this allows the backing or the leader to come out the center of the fly line rather than along the side of it as in the nail knot.

Open Loop - term used to describe what the fly line looks like as it travels through the air during a poor cast; caused by a very wide casting arc.

Pectoral fins - the pair of fins just behind the head of a fish.

Pelvic fins - the pair of fins on the lower body of a fish; also called ventral fins.

Pick-Up and Lay Down - a fly fishing cast using only a single backcast. The line is lifted from the water and a back cast made, followed by a forward cast which is allowed to straighten and fall to the water, completing the cast; good wet fly cast; also useful in bass bugging; most efficient cast to use, when possible, because the fly spends more time in the water (also see presentation).

Presentation - the act of putting the fly on the water and offering it to the fish; the variety of presentations is infinite, and changes with each fishing situation. The object is to present the fly in a manner similar to the natural insect or food form that you are imitating.

Roll Cast - one of the three most basic fly casts; allows a cast to be made without a back cast; essential for use with sinking lines, to bring the line to the surface so it may be picked up and cast in a normal manner.

“S” Cast - cast used to put deliberate and controlled slack into a cast; used in getting a drag free float and in conjunction with mending line (see drag, dead drift, and mending line).

Steelhead - a migratory rainbow trout that reaches great size after spending most of its life in the ocean; also found in the Great Lakes.

Surgeon’s Knot - excellent knot used to tie two lengths of monofilament together; the lines may be of dissimilar diameters.

Tag (Tag End) - the end of the line that is used to tie a knot.

Tailwater - the downstream section of a river or stream found below a large man-made dam.
Tippet - the end section of a tapered leader; the smallest diameter section of a tapered leader; the fly is tied onto the tippet.

Unloading the Rod - unbending the rod. Transferring the casting energy from the rod back into the fly line.

Wind Knot - an overhand knot put in the leader by poor casting, greatly reducing the breaking strength of the leader

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