Definition of purple heart
noun
1 (Purple Heart) (in the US) a decoration for members of the armed forces wounded or killed in action, established in 1782 and re-established in 1932.
2a large tree of the rainforests of Central and South America, with dark purplish-brown timber which blackens on contact with water. - Genus Peltogyne, family Leguminosae: several species
3British informal a purple heart-shaped amphetamine tablet.