A selfie is a photo of ones self that they take and psot online for validation. Personally, I think it's a really stupid thing to do. Posting pics of your face online for strangers validation or approval that you look "lit" or "fire af." The people that do these types of pictures like to get attention and get complients for their ability to use a filter on Snapchat and post that picture everywhere they possibly can. But to each their own I suppose