Real Dictionary

cage
countable noun: A cage is a structure of wire or metal bars in which birds or animals are kept.

Cage in American English
a box or enclosed structure made of wires, bars, etc., for confining birds or animals
John1912-92; U.S. composer
to put or confine, as in a cage
noun: a boxlike enclosure having wires, bars, or the like, for confining and displaying birds or animals
transitive verb: to put or confine in or as if in a cage

cage in British English
noun: an enclosure, usually made with bars or wire, for keeping birds, monkeys, mice, etc
noun: John. 1912–92, US composer of experimental music for a variety of conventional, modified, or invented instruments. He evolved a type of music apparently undetermined by the composer, such as in Imaginary Landscape (1951) for 12 radio sets. Other works inc

cage in Mechanical Engineering
noun: A cage is a device that fits into a rolling bearing and keeps the right amount of space between its individual rollers or balls.