Added 9 October 2026 thermonuclear /ˌθɜː.məʊˈnjuːk.liː.ə/ adjective Categories: Describing WordsRare Words adjective ! Definition from WordNet 3.1, Princeton University. Pronunciation from Wiktionary, via Kaikki.org. More about thermonuclear at Wordnik → Where our words come from → Using nuclear weapons based on fusion as distinguished from fission. Related Words: nuclearatomichotfevercrazethermonasticthermochemicalthermosphericnuclealthermoticmacrothermichyperthermal Back to today's word