mid-14c., "grow fat, increase" (intrans.); c. 1400, "make larger" (trans.), from Old French enlargier "to widen, increase, make larger," from en- "make, put in" (see en- (1)) + large (see large). Meaning "expand in words, speak at large" is from 1650s. There was a Middle English verb large "to extend, increase, make bigger," but it did not survive. Related: Enlarged; enlarging.