Hash tag 'haSHtag / noun 1. (on social media sites such as Twitter) a word or phrase preceded by a pound sign (#) and used to identify messages on a specific topic. #hash tag-it! #haSHtagIT! Game 1. The Hilarious Party game of tagging photos with scandalous, bizarre (and sometimes offensive!) Hashtags! Each round starts with a completely ridiculous photo. Play the best #Hashtagit! legend of the cards in your hand. Be elected best hashtag and win the photo.