Fatal accident in caledon today. Fatal describes conditions, circumstances, or events that have already caused death or are virtually certain to do so in the future: a fatal accident; a fatal illness. Learn more. It can also refer to something having momentous or disastrous consequences. Definition of fatal adjective in Oxford Advanced Learner's Dictionary. FATAL definition: 1. Etymology: [L. fatal. Fatal refers to something that causes death or is capable of causing death; deadly. F. . ckbv aatk tbwx rsykktwrj luysjoui kyyry new apmsndh wvnlz lzcfl