1807; see pea + nut. Earlier, and still commonly in England, ground nut, ground pea (1769). The plant is native to South America; Portuguese traders took peanuts from Brazil and Peru to Africa by 1502 and it is known to have been cultivated in Chekiang Province in China by 1573, probably arriving with Portuguese sailors who made stops in Brazil en route to the Orient.
Peanut butter is attested by 1892; peanut brittle "hard toffee with peanuts roasted in it" is from 1894. Peanut gallery "topmost (and cheapest) rows of a theater" is from 1874, American English, from the peanuts sold as inexpensive snacks; peanuts "trivial sum" is from 1934; peanut for "small or unimportant person" is by 1942. The Peanuts newspaper comic strip by U.S. cartoonist Charles M. Schulz (1922-2000) debuted under that name on Oct. 2, 1950.