What is the meaning of Merry-go-round?

Synonym of carousel (“a pleasure ride, typically found at amusement parks and fairs and accompanied by music, consisting of a slowly revolving circular platform on which are fixed various seats, frequently shaped like horses or other animals, cars, etc., which may also move up and down”).

A freight train of hopper wagons which loads and unloads its cargo while moving continuously on a circular track, often incorporating a balloon loop.

A piece of playground equipment consisting of a circular platform that is made to revolve by pushing while users stand on it.

1. A bustle of activity; also, a meaningless cycle of activity.

   A bustle of activity; also, a meaningless cycle of activity.

   A series of singles and doubles that allows the batting team to score while still having runners on base who can be driven in by the next batter.

   An informal cooperative scheme in which members (often women) regularly contribute money to a pool, the collected money being then paid out to one of the members; this is repeated so that every member eventually receives money. The collected money may also be invested, or loaned to members.

   Source: wiktionary.org