A zoo (short for zoological park, zoological garden, or animal park, and also called a menagerie) is a facility in which animals are confined within enclosures, displayed to the public, and in which they may also be bred.
The term zoological garden refers to zoology, the study of animals, a term deriving from the Greek zōon (ζῷον, "animal") and lógos (λóγος, "study"). The abbreviation "zoo" was first used of the London Zoological Gardens, which opened for scientific study in 1828 and to the public in 1857. The number of major animal collections open to the public around the world now exceeds 1,000, around 80 percent of them in cities.
London Zoo, which opened in 1826, first called itself a menagerie or "zoological forest," which is short for "Gardens and Menagerie of the Zoological Society of London." The abbreviation "zoo" first appeared in print in the UK around 1847, when it was used for the Clifton Zoo, but it was not until some 20 years later that the shortened form became popular in the song "Walking in the Zoo on Sunday" by music-hall artist Alfred Vance. The term "zoological park" was used for more expansive facilities in Washington, D.C., and the Bronx in New York, which opened in 1891 and 1899 respectively.