1. An outdoor area set aside for recreation and play, especially one containing equipment such as seesaws and swings.
2. A field or sphere of unrestricted pleasurable activity: "Foreign affairs had been T.R.'s personal playground during his Presidency" (John Dos Passos).

The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.