Music band is a group of musicians that perform music together. There are different types of bands depending on genre, type and volume of instruments, participants, purpose, etc. A band can be as small as 2 or 3 people, typically with a percussion and one other instrument

Classifications are usually based on genre (eg: rock bands, jazz bands, etc.). Other classifications are based on type of instruments (eg: brass band, pipe band), type of participants or purpose (eg: boy band, military band, church band, etc.)

Adding wind instruments makes it a concert band. Adding more string instruments could mean an orchestra. Classical music settings usually have these. All of these can be called an ensemble.