Origin and history of grew

Middle English grouen, from Old English growan (of plants) "to flourish, increase, develop, get bigger" (class VII strong verb; past tense greow, past participle growen), from Proto-Germanic *gro-, from PIE root *ghre- "to grow, become green" (see grass).

Applied in Middle English to human beings (c. 1300) and animals (early 15c.) and their parts, supplanting Old English weaxan (see wax (v.)) in the general sense of "to increase."

The transitive sense "cause to grow" is attested from 1774. To grow on "gain in the estimation of" is from 1712.

Germanic cognates include Old Norse groa "to grow" (of vegetation), Old Frisian groia, Dutch groeien, Old High German gruoen.