Real Dictionary

kaleidoscope
countable noun: A kaleidoscope is a toy in the shape of a tube with a small hole at one end. If you look through the hole and turn the other end of the tube, you can see a pattern of colours which changes as you turn the tube round.
singular noun: You can describe something that is made up of a lot of different and frequently changing colours or elements as a kaleidoscope.

kaleidoscope in American English
a tubular instrument containing loose bits of colored glass, plastic, etc. reflected by mirrors so that various symmetrical patterns appear when the tube is held to the eye and rotated
noun: an optical instrument in which bits of glass, held loosely at the end of a rotating tube, are shown in continually changing symmetrical forms by reflection in two or more mirrors set at angles to each other

kaleidoscope in British English
noun: an optical toy for producing symmetrical patterns by multiple reflections in inclined mirrors enclosed in a tube. Loose pieces of coloured glass, paper, etc, are placed between transparent plates at the far end of the tube, which is rotated to change the