ADZ is a 3 letter word that starts with A.

1. \Adz\, Adze \Adze\, n. [OE. adese, adis, adse, AS. adesa,
   adese, ax, hatchet.]
   A carpenter's or cooper's tool, formed with a thin arching
   blade set at right angles to the handle. It is used for
   chipping or slicing away the surface of wood.
   
   

2. \Adz\, v. t.
   To cut with an adz. [R.] --Carlyle.