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
basso continuo [I], continuo, b.c., figured bass, thoroughbass, basse chifrée [F], fondement [F], basso generale [I]—During the Baroque Era, a term for an improvised (realized) instrumental accompaniment specified by a symbolic notation for chords and a written bass line (i.e. figured bass). A continuo "part" usually implies multiple (but typically unspecified) instruments, e.g. one for a strong bass line (e.g. cello) and another for chords (e.g. lute, keyboard, organ). A continuo part may be realized by keyboard alone, and sometimes played by a bass melody instrument alone (without harmonies). wiki
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
quartet, quatuor [F], quartett [G], quartetto [I], cuarteto [S]—ensemble or work for four players the most important examples being the string quartet and the piano quartet