meiosis n.

in biology, "division of a cell nucleus," 1905, from Greek meiosis "a lessening," from meioun "to lessen," from meion "less," from PIE root *mei- (2) "small."

Earlier (1580s) it was a rhetorical term, a figure of speech "weak or negative expression used for a positive and forcible one, so that it may be made all the more emphatic," as when one says "not bad" meaning "very good" or "don't mind if I do" meaning "I really would like to," or this example from "Mark Twain":

"YOUNG AUTHOR." — Yes Agassiz does recommend authors to eat fish, because the phosphorus in it makes brains. So far you are correct. But I cannot help you to a decision about the amount you need to eat,—at least, not with certainty. If the specimen composition you send is about your fair usual average, I should judge that perhaps a couple of whales would be all you would want for the present. Not the largest kind, but simply good, middling-sized whales.

 Related: meiotic; meiotically.