Necessary. Opposite of ad lib

Open

Without mute, like senza sord

A musical drama where the words are sung, not spoken

Brass instrument, French ancestor of the tuba

Large group of classical instrumentalists, traditionally comprising strings, woodwind, brass and percussion.

Repeated phrase, often in the bass as an accompaniment

Instruments that produce sounds of definite or indefinite pitch when shaken or struck, including drums, rattles, bells, gongs, and xylophones

Heavy

A relatively short portion of a melodic line which expresses a musical idea, comparable to a line or sentence in poetry

1 - keyboard instrument, whereby strings are struck by hammers. Can be classified as keyboard, percussion or strings!
2 - "soft" dynamic marking

"Pinched." On string instruments, plucking the string

Little. Also poco a poco, little by little

More motion

"Play before." An introductory movement or piece