flowering plant in the mint family, used for thousands of years in medicine and cookery, 1771, from Spanish or American Spanish oregano, from Latin origanus, origanum, from Greek oreiganon, from oros "mountain" (see oread) + ganos "brightness, ornament." In Europe, the dried leaves of wild marjoram; in southwestern America, the name is given to a different, and more pungent, shrub, also known as Mexican oregano.
A staple of Italian cooking, its modern American popularity is said to date to World War II; a 1957 food industry publication in the U.S. says of oregano, "Here is a spice that was unheard of in 99 out of 100 households just a few years ago." Its rise seems to coincide with the popularity of pizza. The older form of the word in English was the Latin-derived origanum (c. 1300), also origan (early 15c., from Old French). Late Old English had it as organe.