As a scientist and college professor, I insist that my students learn definitions. It was not merely an exam exercise, for, without definitions that clearly demark the boundaries of an object, idea, theorem, anatomical structure, and so on, it is not possible to think about their relationship to other objects, ideas, theorems, anatomical structures and etcs.
But too often in fly fishing, terms are used so loosely that they overlap one another. Not the most effective way of learning about the processes of line control. For example, casting and mending are frequently confused. We need to very carefully separate them both in terminology and by what they actually do. So…
CASTING: Those motions necessary to energize the line and send it to target. There are three methods to do this: (1) Wrist Casting in which only the wrist is used to energize the line. (2) Forearm Casting in which the forearm and wrist apply the needed energy. (3) Whole Arm Casting that uses the wrist, forearm, upper arm, and shoulder muscles to sent the line to target.
MENDING: Changing the position of the line after the cast. There are two methods to mend line, and many techniques within each method. (1) On-the-Water Mending where the angler casts the line, and after it has fallen to the surface, it is then flopped, rolled, stacked, or otherwise manipulated to reposition the line. (2) In-the-Air Mending (also called Aerial Mending) in which the fly rodder makes the cast, and as the line is travelling to target (still in the air), the rod is moved to reposition the line. This leads to the Reach Mend, Parachute Mend, Puddle Mend, Reached Puddle, Curve Mend, Reached Curve, Hump Mend, and so on.
Knowing these definitions greatly helps the fly caster develop the needed cast or mend without confusion.
Whether casting and/or mending by horseback, wading, or from a boat, the fly rodder must see the processes as individual rod manipulations, separate from one another.