hashtag

hash·tag

H h

Definitions of hashtag word

noun hashtag (on social media websites) a word or phrase preceded by a hash mark (#), used within a message to identify a keyword or topic of interest and facilitate a search for it: The hashtag #sandiegofire was used to help coordinate an emergency response to the fire. 1
noun hashtag a hash mark used in this way. 1
noun hashtag (on social media sites such as Twitter) a word or phrase preceded by a hash or pound sign (#) and used to identify messages on a specific topic. 1
countable noun hashtag On the Twitter website, a hashtag is a word or phrase that has a hash (#) in front of it, to show that it is the topic of a message. 0
noun hashtag (on the Twitter website) a word or phrase preceded by a hash mark, used to denote the topic of a post 0

before 2005

One of the 1% newest English words

2005-10; hash (mark) + tag1 (in the sense “a label or keyword”)

noun

adjective

verb

adverb

pronoun

preposition

conjunction

determiner

exclamation

A common word. It’s meaning is known to most children of preschool age. About 99% of English native speakers know the meaning and use the word.

Most Europeans know this English word. The frequency of it’s usage is somewhere between "mom" and "screwdriver".