A "Retweet" is a feature on the social media platform Twitter that allows users to share someone else's tweet with their own followers. When a user retweets, the original tweet is displayed on their profile and in their followers' feeds, helping to spread the message further. Retweets can be done with or without adding a comment. A simple retweet shares the original content as is, while a "quote retweet" allows the user to add their own thoughts or context. This feature encourages engagement and conversation among users on Twitter.