Noah Webster
Adult
ADULT', noun [Latin adultus, grown to maturity, from oleo, to grow; Heb. to ascend.]
Having arrived at mature years, or to full size and strength; as an adult person or plant.
ADULT', noun A person grown to full size and strength, or to the years of manhood. It is also applied to full grown plants. among civilians, a person between fourteen and twenty-five years of age.