Sheet music terminology

Question

I am writing software for managing sheet music. Now I want to translate the software to English and need some common English words for sheet music related terms (single words preferred):

1. a single music piece for one or more instruments (e.g., a jazz piece with sheets for for 15 different instruments)

2. a "sheet music book" containing many single music pieces (e.g., Chopin Nocturnes, Jazz Real Book, Tchaikovsky Piano Concerto No 1)

3. as part of (1): sheet music for a single piece and a single instrument (e.g., Tchaikovsky Piano Concerto No 1 - Clarinet part only

4. what it is called when a musician makes music (including rehearsals and performances)?

5. a group of musicians playing together

Since the software should be applicable to any kind of music style (jazz, classical, ...) and any kinds of instruments and groups of musicians (single piano player, complete orchestra, marching band,...), what are the best terms for 1. to 5.?

With my little English knowledge, I came up with these terms:

for 1.: song

for 2.: songbook

for 3.: voice

for 4.: performance

for 5.: band

Are there better (more popular) English terms?

EDIT:

My first language is German. My German terms are:

for 1.: Heft

for 2.: Stück

for 3.: Stimme

for 4.: Spielereignis

for 5.: Band

I am not fully happy with that terms, but in German we don't have common words that cover all kinds of music.

Answer 1

For goodness sake, why don't you tell us what language you are translating from, and the terms you would use in that language. The chances that no-one here speaks the same language are close to zero.

1.: song: No. "piece" (or possibly "composition") Calling Beethoven's fifth symphony a "song" is not generally regarded as educated.

2.: songbook: No. (same reason as above). Usually an "album" (which works for just about any genre, I think)

3.: voice: No. Usually "voice" refers to either "a human voice" (i.e. sung), or any of the constituent parts of a polyphonic composition. Probably "part" is best.

4.: performance: Yes.

5.: band: No, since this could not include an orchestra or a group of choral singers (etc etc). Not clear what would be best, since it depends on the context.

You could also look at (for example) the terms used by software such as Musescore, which will be available in "your language" and also English.