bagatelle—a short character piece, typically of a light nature. Meaning "trifle" or "nothing of importance." Used for a variety of short pieces.
carol—A song of praise or joy, especially for Christmas. An old round dance often accompanied by singing.
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
duo, duet, dueto [S], duetto [I], duett [G]—a work for two instruments; the ensemble itself
Forlane, Forlana, Furlana—A traditional dance from France via Italy that became a Baroque-era courtly dance. Occasionally referenced in instrumental suites.
Fughetta—a small (short) fugue
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
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
romanza, romanze, romance—a title for a work or movement implying a rather personal, tender, sentimental or amorous tone. Typically, lyrical.
suite—a set of instrumental pieces (movements) played together to create a larger whole. Suites tend towards collections of dances, frequently in the same key, preceded by a prelude, introduction or overture.