古英語のmyrge、楽しい、嬉しいから、原語ゲルマン語の*murgijaz、一時的な、PIE *mreghu、一時的なから、語源はbriefと同じ、省略する。briefからjoyfulへの語源は、喜びは常につかの間であるという心理的効果からかもしれない。
Bot vchon enle we wolde were fyf, te mo te myryer. [c. 1300]The word had much wider senses in Middle English, such as "pleasant-sounding" (of animal voices), "fine" (of weather), "handsome" (of dress), "pleasant-tasting" (of herbs). Merry-bout "an incident of sexual intercourse" was low slang from 1780. Merry-begot "illegitimate" (adj.), "bastard" (n.) is from 1785. Merrie England (now frequently satirical or ironic) is 14c. meri ingland, originally in a broader sense of "bountiful, prosperous." Merry Monday was a 16c. term for "the Monday before Shrove Tuesday" (Mardi Gras).