Real Dictionary

musical chairs
uncountable noun: If you describe the situation within a particular organization or area of activity as musical chairs, you are critical of the fact that people in that organization or area exchange jobs or positions very often.
uncountable noun: Musical chairs is a game that children play at parties. They run round a row of chairs while music plays and try to sit down on one when the music stops.

musical chairs in American English
a game in which the players march to music around empty chairs (always one fewer than the number of players) and rush to sit down each time the music stops: the player with no seat is eliminated in each round
noun: a game in which players march to music around two rows of chairs placed back to back, there being one chair less than the number of players, the object being to find a seat when the music stops abruptly. The player failing to do so is removed from the gam

musical chairs in British English
a party game in which players walk around chairs while music is played, there being one fewer chair than players. Whenever the music stops, the player who fails to find a chair is eliminated