... Aussiefly's Dictionary of fly fishing terms

Fly Fishing Glossary
This is a every growing list of Terms used in Fly Fishing, feel free to add to the list by contacting Uncle Barry

G
Gape - space between the point of the hook and the shank
Gel-spun polyethylene - A synthetic fiber that is extremely thin, supple, slippery, very abrasion resistant, and strong. It is stronger than steel for its size. It is often used as a braided fly line backing where large amounts of backing are needed and space on the reel is limited
Ghillie - a person employed as guide to anglers on salmon fishing waters
Gold Head - A Bead Head fly uses a metal bead to simulate the thorax on a nymph or wet fly and to add weight to the fly
Golden Pheasant - Bird whose crest, neck and wing feathers are used extensively in fly patterns
Graphite - the most popular rod-building material in use today; offers the best weight, strength, and flex ratio of any rod building material currently available

H
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
Hackle pliers - fly-tyer's tool for wrapping the hackle feather around the hook
Hang over to much red wine
Hair stacker - small tube which is used to level a bunch of hair, usually deer hair
Hare's mask - the facial area of the hare used for fly tying
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 lesser populations of aquatic insects
Hatch - a large number of flies of the same species
Headwaters - upstream section of the river before the main tributaries join it. This section is typically much smaller in width and flow than the main section of the river
Hen Hackle - Hackle feathers from a hen chicken characterized by soft, wide feathers
Herl Feathers - used for tying with long individual barbules each having short dense fibers. Used as tails and to make fly bodies, usually from Peacock and Ostrich
Hollow Hair - hair from some animals is mostly hollow, thus holding air and making these hairs float. Ideal for tying dry flies and bass bugs. Antelope, deer, and elk all have hollow hair
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 and the fish sought