Reference

A plain-English fly fishing glossary

The vocabulary is the barrier far more often than the casting is.

The water and the cast

TermMeaning
SeamThe line where fast water runs alongside slow water. Where fish hold.
Drift lineThe visible ribbon of foam and debris tracking down a seam.
MendFlicking a loop of line upstream after the cast to stop the current dragging the fly.
DragThe fly being pulled unnaturally across the current by the line. The main reason fish refuse.
Dead driftA fly travelling at exactly the speed of the current, under no tension.
Pocket waterBroken water around boulders, full of small holding spots.

The insects

TermMeaning
NymphThe underwater larval stage of an aquatic insect, and the flies that imitate it.
EmergerAn insect in the act of hatching, stuck in the surface film. Often what fish are actually eating.
DunA freshly hatched adult mayfly on the surface, wings up, drying them.
SpinnerThe final adult mayfly stage, which mates and falls spent on the water.
TerrestrialA land insect blown onto the water — hoppers, ants, beetles.

The tackle and the fly

TermMeaning
TippetThe fine end section of leader that the fly is tied to.
X ratingTippet diameter. Bigger number means thinner: 6X is finer than 4X.
HackleFeather wound round the hook to suggest legs and, on a dry fly, to float it.
DubbingFine fur or synthetic fibre twisted onto thread to form a fly's body.
Bead headA metal bead at the head of a fly to sink it. Tungsten sinks about twice as fast as brass.
SighterBrightly coloured leader section watched for takes when euro nymphing.
FloatantGel or powder that keeps a dry fly in the surface film.