What is the meaning of Poppy?

Any plant or species of the genus Papaver, herbs with showy polypetalous flowers and a milky juice. From one species (Papaver somniferum) opium is obtained, though all the species contain it to some extent; also, a flower of the plant. See Illust. of Capsule.

Source: Webster’s Revised Unabridged Dictionary (1913), via OPTED