adagio [It]—slow tempo, often implying a lyrical, poignant character
allegretto—moderately quick tempo. slower than allegro but faster than andante
allegro [I]—fast, lively tempo. From the Italian word for cheerful or gay.
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
finale [I], final [F]—The final movement, sometimes explicitly titled thus
opus [L], opera[pl], Op., Opp, WoO, Op. posth—work, as in a work of art. For unique identification, publishers/composers often assign an "opus number", abbreviated as "Op." (e.g. Op. 1). A range of works by opus number, uses the plural "opp." (e.g. "Opp. 1-3"). A single opus number may refer to a collection of works (e.g. a set of quartets) giving rise to designations like "Op. 1, No. 4". For misc. works without opus numbers, "WoO" is often used (e.g."Without Opus"). Posthumously assigned numbers may use "Op. posth". Opus numbers may not precisely reflect chronology (publication vs. composition), can be erroneous, sparse or duplicative. Thus, the works of some historically important composers may use separate catalog numbers (e.g. Bach, Haydn, Schubert). See wiki
scherzo—lively, brisk, typically in a triple meter; usually a three-part form with central, contrasting trio
string trio, Streichtrio [G], Trio d'archi [I], Trio de cordes [F], Trío de cuerdas [S]
—a work for three stringed instruments, most commonly violin, viola and cello. A more rarefied form than the string quartet perhaps because the texture is sparse (each instrument highly exposed) and the means more difficult for natural harmonic richness. But these become challenges and assets in the great trios. Trios almost always emphasize countrapuntal writing with each of the three players in strong relief.