A choir is a group of singers who perform together, with or without accompaniment from musical instruments. You may also hear a choir referred to as a chorus. Choirs around the world are incredibly varied, from casual secular groups which meet and perform periodically to highly organized church choirs featuring an array of very disciplined singers. Both secular and religious music is composed for the choir, and some choirs also adapt existing musical pieces for performance.
The history of the chorus is quite ancient. The Greeks used a chanting chorus to accompany stage performances, for example, and the medieval church also utilized chanted plainsong to accompany religious services. Gradually, the concept of a polyphonic or “many voiced” choir began to emerge, with musical compositions featuring multiple parts which could be sung together or individually, and modern choirs typically perform polyphonic compositions which showcase a range of voices.
There are many different types of choir. Mixed choirs feature both men and women, and it is also possible to find men's choirs, women's choirs, and children's choirs, including children's choirs divided by gender. The type of compositions performed varies considerably as well, depending on the members of the choir and the environment in which they perform.
Typically, a choir is led by a conductor, in much the same way that a conductor leads an orchestra. Singing in a choir isn't just a matter of opening your mouth and belting out tunes, either. The members of the choir have to be perfectly coordinated or the performance will sound “off,” although it may be difficult to pin down why the performance sounds wrong. A good choir is composed of people who sing together, perfectly on pitch, with voices and volume levels which complement each other.
When a choir is well-organized, their performances can be distinctive and very compelling. Some very famous works have been composed for choirs, including the oratorios of Handel. Choral performances are especially popular in the holiday season, and in classical music festivals, although choirs can also perform jazz compositions and works from other musical genres.
Some communities have casual community choirs which welcome anyone who wishes to join. Typically people who want to join such choirs must demonstrate an ability to sing and read sheet music, and they must be able to commit to a practice schedule. Choirs can also be found in educational institutions, religious parishes, and collectives of musical performers such as city orchestras and operas.