Added 9 October 2026 heater /ˈhitɚ/ noun Categories: ThingsActionsUncommon Words noun ! Definition from WordNet 3.1, Princeton University. Pronunciation from Wiktionary, via Kaikki.org. More about heater at Wordnik → Where our words come from → Device that heats water or supplies warmth to a room. (baseball) a pitch thrown with maximum velocity. he swung late on the fastball Related Words: bulletwarmersmokehummerfastballheatingfurnacekilnstovefirewoodboilercooler Back to today's word