17 -- brit guard? pickguard?

18 -- ladder bracing

(very game guesses for a non-guitar geek, Mary!)

So far:

1) Rosewood
7) Heel (Heal)
11) Tuner (Too Near)
12) Mother of Pearl (S. Buck)
14) Saddle(s) and Nut(s)
15) Truss Rod
16) Maple (May Pole)