A harbinger is a sign or indication of something to come, often associated with an omen. In various cultures, harbingers are seen as forewarnings that signal future events, particularly those that are significant or ominous. They can take many forms, such as natural phenomena, animals, or specific occurrences that suggest a change is imminent. In literature and folklore, harbingers often serve as symbols that foreshadow events. For example, the appearance of a black cat might be considered a harbinger of bad luck, while the arrival of spring can signify renewal and hope. These symbols help convey deeper meanings and themes within stories.