Rabbets

[Willallison]

How on earth did 'Rabbets' get their name? My best guess is that it was written many moons ago by someone who couldn't spell rebate!

[Dave Fleming]

Rather than a misspelled word, more like a regional difference in pronunciation.
Example here in the States, on the East Coast the process of filling a Carvel planked boats seams with cotton/oakum is called CAULKING, whilst on the West Coast it is called CORKING.
On the East Coast the wood pieces for filling countersunk screw holes are called BUNGS whilst on the West Coast PLUG is more commonly used.
The longitudinal wood pieces laid outside MOULDS* for alignment and reinforcement are called RIBBANDS. The same term is used in heavy concrete construction for the horizontal wood timbers that help tie concrete forms together.
* There is another one, Molds and Moulds, same meaning but different spelling depending upon geographical area.
My favourite and MMD will recall the discussion on it is, HARPIN. A structural member of a Carvel planked wooden boat almost solely used on the West Coast of North American ( to the best of my knowledge that is.)

I realize that this rambling does not directly answer your question but perhaps it does explain a bit about words and regional usage.

[Willallison]

...so the short answer is yes - a rabbett is simply a rebate by another name ?!? :D