canon, kanon [G]—a strict form of polyphonic, contrapuntal imitation where a series of staggered parts share the same melodic material separated by time and possibly an interval creating both linear and horizontal counterpoint; a simple form of canon is a round (e.g. "Row, Row, Row your Boat")
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
elegy, elégie [F], elegie [G], elegisch, elegiaco, elegaico [I], élégiaque [F]—a plaintive, mournful poem, more specifically a lament for the dead. Usually implies a slow tempo, a minor key and a dark poignancy with potential spikes of tragic agony or, just as well, a gentle, bright flowering into nostalgic love of great tenderness. A musical narrative combining all of these moods is a hauntingly faithful representation of grief
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
piece, pièce [F], stück [G], stücke [pl], pezzo [I], pezzi[pl]—a single-movement, self-sufficient musical work. Often used for short, individual works in a set or simply to indicate brevity without a titular suggestion of form or character.Chiefly contrasted with the term "movement", a piece which is an integral part of a larger whole without which it would be incomplete.
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
serenade, serenada, serenata [I], sérénade [F]—A suite of movements like a divertimento with similar connotations of lightheartedness, pleasure and relative calm with an emphasis on lyricism and often beginning with a march. Historically evokes the evening, outdoors, an honorific or amorous tribute, especially from a suitor to a lover in a window or balcony. The word serenade has its Latin origins the Latin word for "calm" or serene. wiki