A hashtag is a word or phrase preceded by the pound sign (#) used on social media platforms to categorize content. It helps users find posts related to specific topics, events, or trends. For example, using the hashtag #Travel allows people to discover travel-related posts easily. Hashtags originated on Twitter in 2007 and have since become popular across various platforms like Instagram, Facebook, and TikTok. They can enhance visibility and engagement by connecting users with similar interests, making it easier to participate in conversations or follow specific themes.