a rattlesnake, Crotalus cerastes, of southwestern U.S. and northern Mexico, that has a hornlike projection over each eye and that moves in loose sand by raising loops on the body and displacing them sideways.
any Old World snake that moves by sidewinding, as various species of Bitis and Cerastes.
(initial capital letter) an air-to-air, supersonic weapon that intercepts and destroys enemy aircraft using an infrared homing-guidance system.
small horned rattlesnake of southwestern U.S., 1875, American English, from side (adj.) + agent noun of wind (v.), so called in reference to its "peculiar lateral progressive motion." Also sidewiper (1888).