accelerando (accel.)
gradually growing faster
accidental
chromatic alteration of a note from the key signature until the next bar line (can be extended by a tie)
ad libitum (ad lib) OR a piacere
at pleasure, at will
a due (a 2)
for two parts
affetuoso
tenderly, with feeling
alla breve
2/2 time, cut time
allargando
getting slower and louder
amaroso
with love, with warm feeling
animato OR con anima
lively, animated, spirited