From Longman Dictionary of Contemporary Englishplaypenplay‧pen /ˈpleɪpen/ noun [countable] DHTan enclosed area in which a very small child can play safely, that is like an open box with sides made of bars or a net
Examples from the Corpus
playpen• The Third World should no longer serve as a playpen for greedy, killer interventionist maneuvers by aging cold warriors.• Through the living-room window he can see a playpen, and a child's pot standing on the table.• I wouldn't advocate the academic playpen scenario but I seem to remember having some quality of life.• McNair has himself a guaranteed Super Bowl for his new playpen in 2004.• Do not use in cribs, beds, carriages, or playpens.• Separate political playpens based on homogeneous constituencies force people apart, not together.• He walked over to the playpen and picked up Christina and held her soft heat against his chest. 