hashtaghash‧tag1, hash tag /ˈhæʃtæɡ/ noun [countable]a word in a Twitter message with # in front of it, which indicates what the message is about. People can search for hashtags in order to find messages about a particular subject.
hashtag1nounhashtag2verb
hashtaghashtag2 verb [transitive]to put a hashtag before a word on Twitter