phenomenon that is believed to foretell the future
An omen is a sign that is thought to foretell the future, often signifying the advent of change. The word can mean something either "good" or "bad" is about to happen. The origin of the word is unknown, although it may be connected with the Latin word audire, meaning "to hear". An example from the past, babies born with birth defects were believed to be a bad or evil omen.