ETYM Old Eng. fle, flee, as. fleá, fleáh; akin to Dutch vtoo, Old High Germ. flôh, German floh, Icel. flô, Russ. blocha; prob. from the root of Eng. flee. Related to Flee.
Wingless insect of the order Siphonaptera, with blood-sucking mouthparts. Fleas are parasitic on warm-blooded animals. Some fleas can jump 130 times their own height.
Species include the human flea Pulex irritans; the rat flea Xenopsylla cheopsis, the transmitter of plague and typhus; and (fostered by central heating) the cat and dog fleas Ctenocephalides felis and c. canis.
Any wingless blood-sucking parasitic insect noted for ability to leap.