[1660–70; under- + plot]This word is first recorded in the period 1660–70. Other words that entered Englishat around the same time include: aspirate, interleave, joke, mainstream, vocalizeunder- is a prefixal use of under, as to indicate place or situation below or beneath (underbrush; undertow); lower in grade or dignity (undersheriff; understudy); of lesser degree, extent, or amount (undersized); or insufficiency (underfeed)