allegro [I]—fast, lively tempo. From the Italian word for cheerful or gay.
andante [I]—moderately slow tempo (e.g. walking). Faster than adagio but slower than allegretto
chamber music, Kammermusik [G], musique de chambre [F], musica da camera [I], musica cameralis [L]—"Classical Music" for a small ensemble, generally 8 or fewer players with a canonical emphasis on 3-6 players. explore
con [I,S]—with
duo, duet, dueto [S], duetto [I], duett [G]—a work for two instruments; the ensemble itself
improvisando [I], improvisato—improvised, with improvisation
moderato [I], moderamente, modéré [F], modérément [F]—moderately, at a moderate tempo, applying a touch of restraint to its related word(s), e.g. allegro moderato
moto, con moto, di moto—motion, with motion. Somewhat more lively than its context would suggest, e.g. "andante con moto", a little more lively than andante
prelude, prélude, präludium [G], präludien [G, pl], praeludium, preludio—a movement preceding another almost by way of introduction: to let listeners and players acclimate, often to prepare for greater demands ahead
presto—very fast, more so than allegro.
quasi—almost, almost like, as if
sostenuto [I], soutenu [F]—sustained, perhaps a bit slow
troppo [I], non troppo, trop [F]—too, too much. non troppo means "not too much". e.g. "Allegro ma non troppo" means fast, but not too much