A musical ensemble is a group of several instruments used to perform music. There are several denominations according with their size and composition.
- Duet: Two instruments
- Trio: Three instruments
- Quartet: Four instruments. The most common is the string quartet, composed by two violins, viola and violoncello.
- Quintet: Five instruments. The most usual string quintet is
similar to the quartet, but with the viola duplicated. In same cases, though, is the violoncello what is duplicated, as in the famous Schubert's string quintet D.XXX. A piano quintet is usually a string quartet plus piano.
- Sextet: Six instruments
- Septet: Seven instruments
- Octet: Nine instruments
More instruments but still not too many are usually refered as a Chamber Orchestra.
A choir is a group of voices.
A String Orchestra has only strings, i.e. violins, violas, violoncellos and basses.
A Symphonic Orchestra is a large body of several tens and often more that a hundred musicians, divided in groups of instruments: Violins I and II, Violas, Violoncellos, Basses, woodwinds, brass, percusion, and some times more.
There is no difference between a Symphonic, a Philarmonic, a Symphophilarmonic, etc. orquestras. They are only names to distiguish them when there is more that one in a city.