Steve, your idea is interesting. I want to hear more about it...
Hope it will do some good there, Tom. Thanks.
Marc, that is the primary definition... But here is a quote from the Webster's Encyclopedic Unabridged Dictionary of the English Language (1989):
Caul (2): n. a form or plate for pressing a veneer or veneers being glued to a backing or to each other. [< F cale shim < G Keil wedge]
Would seem appropriate to laminated bows, at the least...
I have also heard it called a "form", but this is usually in the context of laminated bows, both natural and of modern materials.
I have heard the term "caul" used in wood working shows for the blocks of wood used between a clamp and a piece of work, to avoid marring it. Note the French and German words of possible origin in the above definition...
For bowmaking purposes, I would propose the following simple definitions, which reflect current use in "bowyerese", as far as I can tell:
Form: A piece of wood or other sturdy material shaped depending on desired bow profile so that laminations of wood and/or modern materials may be clamped into or against it, in order to give the shape of the form to the glued up bow blank.
Caul: A piece of wood or other sturdy material shaped in such a way that a bow or bow stave can be clamped against or into it during the heat straightening or belly tempering process, in order to impart the desired shape, and/or correct crookedness or twist.
[Edited to put quote in quotation bars. Ken]
[Edited to add missing word. Ken]