any of a family (Dactylopiidae) of scale insects, esp. one (Dactylopius coccus) that has a brilliant-red body fluid, feeds on certain cactuses, is found chiefly in Mexico, and was formerly much used as a source of cochineal
See cochineal insect in American Heritage Dictionary 4
noun
Any of several red scale insects of the family Dactylopiidae that feed on cacti, especially the prickly pear, and range from the southwest United States to Central America.