means An outdoor area, usually with equipment like swings and slides, set aside for children to play.

from A transparent compound of "play" and "ground." "Play" descends from Old English "plega" (meaning quick movement, sport, or frolic), and "ground" from Old English "grund" (the bottom or earth underfoot). Stitched together, the word names exactly what it says — ground for play — and only later narrowed from any patch of land used for games to the swing-and-seesaw kingdoms we picture today.