These words refer to musical groupings composed of varying numbers of instrumentalists. Of all these words, orchestra can indicate the largest group of musicians; in reference to classical music, it suggests the full-scale symphonic group with its complement of strings, woodwinds, brass and percussion. While such an orchestra might typically have as many as a hundred players, the word itself can be qualified to suggest a smaller group: a chamber orchestra of twelve musicians. The one strict difference between an orchestra and a band does not pertain to size but rather to the fact that an orchestra has a string section and a band does not. While a variety of music exists for performance by a band , the word usually suggests light or popular music: rousing marches played by the military band . When the reference of both words is to popular or jazz music, performed for listening or dancing, the implications of both words change. In this case, orchestra can refer to a group of any size: a nightclub orchestra ; a six-piece orchestra . This word is often used to give status to what is in fact a popular dance or jazz band , whether or not it has a complement of strings. Both words here might, most typically, refer to groups having something like twenty or fewer players.

Ensemble is the least specific of these words as to the nature and size of the group of players. Technically, two or more players can make an ensemble , but the word usually suggests a grouping of several players, both in classical and popular music: a chamber ensemble ; a Dixieland ensemble . Since the word can refer to any group acting together in concert, it can also apply to vocal groups as well as instruments: a choral ensemble . Combo is the more informal word for a group of several jazz or popular instrumentalists: a cocktail combo ; a bop combo ; a rock ‘n’ roll combo . Quartet , of course, is specific in indicating four musicians; otherwise it is completely open to qualification by context: a string quartet ; a woodwind quartet ; a campfire quartet ; a rock quartet . Other words indicating an exact number of players are comparable in use to quartet : duet, trio, quintet, sextet, septet, octet.