say it: thur-moh-NOO-klee-ur
thermonuclear is an adjective meaning "using nuclear weapons based on fusion as distinguished from fission". It carries one recorded sense.
using nuclear weapons based on fusion as distinguished from fission
Definitions, synonyms and semantic relations for thermonuclear come from Princeton University’s WordNet. The pronunciation comes from the CMU Pronouncing Dictionary. Commonness is measured against a corpus of everyday English. .