A composer (Latin compōnō; literally “one who puts together”) is a person who creates or writes music, which can be vocal music (for a singer or choir), instrumental music (e.g., for solo piano, string quartet, wind quintet or orchestra) or music which combines both instruments and voices (e.g., opera or art song, which is a singer accompanied by a pianist). The core meaning of the term refers to individuals who have contributed to the tradition of Western classical music through creation of works expressed in written musical notation (e.g., sheet music scores).
Many composers are also skilled performers, either as singers, instrumentalists, and/or conductors. Examples of composers who are also well known for their ability as performers include J. S. Bach (an organist), Mozart (violin and piano), and Beethoven, Liszt and Chopin (all skilled pianists). Involvement in practical music-making provides a composer with insight into the diverse musical elements needed for a good piece of music and it can give them practical guidance with their compositions.
In broader usage, “composer” can designate people who participate in other musical traditions who create music, as well as those who create music by means other than written notation: for example, Blues or folk singers and guitarists who create songs through improvisation and recording and popular music writers of musical theatre songs and arrangements. In many popular music genres, such as rock and country, musicians who create new songs are typically called songwriters.