hashtag

English

Etymology

From hash +‎ tag.

Noun

hashtag (plural hashtags)

1. (Internet) A tag embedded in a message posted on the Twitter microblogging service, consisting of a word within the message prefixed with a hash sign.
   • 2009, Paul McFedries, Pete Cashmore, Twitter Tips, Tricks, and Tweets

     You can also search for a hashtag by typing a topic (without the #) in the search box and clicking Search.

   • 2009, Alistair Croll, Sean Power, Complete Web Monitoring

     While hashtags aren't formally part of Twitter, some clients, such as Tweetdeck, will persist hashtags across replies to create a sort of message threading.

   • 2011, Rory Stewart, "Here we go again", London Review of Books, 33.VII:

     The planes are moving into position. The foreign ministers of minor Arab states are taking calls on their cell-phones from Western politicians. Twitter accounts explode around the Libyan hash-tag.