flea

A small, wingless insect that as an adult is a blood-feeding external parasite of warm-blooded animals (mostly mammals, but including some birds); body flattened from side to side, usually hairy; mouthparts specialized for piercing and sucking; hindlegs adapted for jumping; larvae maggot-like, feeding on organic refuse around domicile of host; c.1750 species, many of medical and veterinary importance as carriers of disease. (Order: Siphonaptera.)

Flea is the common name for any of the small wingless insects of the order Siphonaptera (some authorities use the name Aphaniptera because it is older, but names above family rank do not follow the rules of priority, so most taxonomists use the more familiar name).