atrocity (n.) Look up atrocity at Dictionary.com
1530s, from Middle French atrocité or directly from Latin atrocitatem (nominative atrocitas) "cruelty, fierceness, harshness," noun of quality from atrox "fierce, cruel, frightful," from PIE *atro-ek-, from root *āter- "fire" (see atrium) + *okw- "see" (see eye (n.)); thus "of fiery or threatening appearance." The meaning "an atrocious deed" is from 1793.