adagio [It]—slow tempo, often implying a lyrical, poignant character
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
maestoso—With dignity and nobility; majestic
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
piano quartet, Klavierquartett [G], Quatuor avec piano [F]—a ensemble (work) comprising violin, viola, cello and piano. Most of the great Classical and Romantic composers produced one or more works for this combination of which many are masterworks of chamber music.
Siciliana, Siciliano, Sicilienne—a musical form often included as a movement within larger pieces of music starting in the Baroque period. It is in a slow 6/8 or 12/8 time with lilting rhythms making it somewhat resemble a slow jig, and is usually in a minor key. It was used for arias in Baroque operas, and often appeared as a movement in instrumental works. The siciliano evokes a pastoral mood, and is often characterized by a large number of dotted rhythms. wiki