1. Also called cantharides . a preparation of powdered blister beetles, esp. the Spanish fly, used medicinally as a counterirritant, diuretic, and aphrodisiac.
2. Also, Spanishfly . Also called cantharis . a common European blister beetle, Cantharis ( Lytta ) vesicatoria, that yields this preparation.
[ 1400-50; so called from the fact that the beetles are found in abundance in Spain ]