So are we going with [A]s? If so...
*opens dictionary*
Animated
Andante
Anchor
Anoxia
Anno Domini (could be [Ad])
Aplomb
Anticlimactic
Apparatus
Aragonite
Arcturus
Arouse
Armada
Arsenic
Association
Askew
Atomic (taken??)
Astatine
AuDiO
Avenge
Avalanche
Avenue
Ayrshire
Azalea
Azimuth
Azurite