say it: OH-vur-nahyt
overnight is an adverb and adjective meaning "during or for the length of one night". It carries 3 recorded senses.
during or for the length of one night
“the fish marinates overnight”
happening in a short time or with great speed
“these solutions cannot be found overnight!”
Definitions, synonyms and semantic relations for overnight come from Princeton University’s WordNet. The pronunciation comes from the CMU Pronouncing Dictionary. Commonness is measured against a corpus of everyday English. Full sources and licences.