Yours, Etc.: Origins and Uses of 8 Sign-Offs
1807, earlier ground nut, ground pea (1769). The plant is native to S.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 attested by 1892; peanut brittle is from 1894. Peanut gallery "topmost rows of a theater" is from 1874, American English; peanuts "trivial sum" is from 1934.
: a peanut operationnoun
A small or trivial person; something insignificant (1934+)