any of numerous small, round, often brightly colored and spotted beetles of the family Coccinellidae, feeding chiefly on aphids and other small insects, but including several forms that feed on plants.
la·dy·bug (lā'dē-bŭg') n. Any of numerous small, rounded, usually brightly colored beetles of the family Coccinellidae, often reddish with black spots and feeding primarily on insect pests, such as scale insects and aphids. Also called lady beetle, ladybird.
[Probably from its seven spots being considered a symbol of the seven sorrows of the Virgin Mary.]