Added 8 October 2026 playpen noun Categories: ThingsRare Words noun ! Definition from WordNet 3.1, Princeton University. More about playpen at Wordnik → Where our words come from → A portable enclosure in which babies may be left to play. Origin From play + pen. From Wiktionary, via Kaikki.org (CC BY-SA) Related Words: penparkfleetstockparcplayparkplaygroundplaylotplaysetsoftplayplaybarn Back to today's word