n.giant sea reptile from the Mezozoic, 1879, from Modern Latin (coined 1868 by E.D. Cope), from Greek elasmos "metal plate" (from elan "to strike;" see elastic) + -saurus. if (window.googletag) {googletag.cmd.push(function() { googletag.display('dcomMobileSERPDisplayTopAd-300x250'); });} else {console.error('googletag not defined, dcomMobileSERPDisplayTopAd-300x250');}