Pronunciation: (sīd'wīn"dur),[key] —n. 1. a severe swinging blow from the side.
2. 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.
3. any Old World snake that moves by sidewinding, as various species of Bitis and Cerastes. 4. (cap.) an air-to-air, supersonic weapon that intercepts and destroys enemy aircraft using an infrared homing-guidance system.