hashtag

American  

[hash-tag] / ˈhæʃˌtæg /

noun

1. (on social media websites)

   1. 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.

   2. a hash mark used in this way.

2. 1. a word or phrase preceded by a hash mark (#) or by the word hashtag , used to add wit or emphasis to a spoken or written statement.

   2. a hash mark or the word hashtag used in this way, as in the sentence His goodbye was so hashtag awkward.

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verb (used with or without object)

hashtagged, hashtagging

1. to add a hashtag to (a word, topic, or message).

   Someone on Twitter just hashtagged the film festival.

hashtag British  

/ ˈhæʃˌtæɡ /

noun

1. (on the Twitter website) a word or phrase preceded by a hash mark, used to denote the topic of a post

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Usage

What does hashtag mean? A hashtag is a word or phrase preceded by a hash mark (#), also known as a pound sign, used primarily on social media. On social media, hashtags provide users a way to search for posts related to the word or phrase in the hashtag. You can click on a hashtag to see a list of recent posts that include that keyword. (A couple of our favorites are #WordOfTheDay and #WordNerd.)To hashtag means to add a hashtag to a word, topic, or message, as in We hashtag our posts about history with #HistoryMatters so you can find them easily. Example: Use the hashtag #petthedog with a video of you petting your dog for a chance to win our contest.

Etymology

Origin of hashtag

First recorded in 2005–10; hash (mark) + tag ¹ (in the sense “a label or keyword”)

Explanation

A hashtag is a keyword or phrase that's used on social media. By searching for a certain hashtag, you can easily find the cute cat content you're looking for. To create a hashtag, type # (which is variously called the "number sign," "pound sign," or "hash") followed by a word. You might post about a successful pie-baking experiment and use the hashtags #pie, #sourcherrypie, and #baking. And if you're looking for content about capybaras, just click on #capybara and you'll see a list of every photo or post with that hashtag. The very first hashtags appeared on Twitter in 2007, and they quickly spread across all social media.

Example Sentences

Then, finally, the truth about the fact is revealed, with Wiles sharing that her neighbors were of a more high-brow Hollywood class, sharing an image of Craig and Weisz with the hashtag #holyairball.

From MarketWatch • Apr. 15, 2026

With the understanding that nothing dispels an air of mystery like a hashtag, a number of modern speakeasy successors have clamped down on social-media posts or even phone use altogether.

From The Wall Street Journal • Apr. 14, 2026

More than 300,000 videos on TikTok have been tagged with a hashtag related to the animals.

From BBC • Mar. 31, 2026

“Michael messaged me and asked if I had time for a quick call,” said Patriots megafan Brian Babikian, whose persistent posts inspired both the #EndFanatics hashtag and the account, @End_Fanatics.

From Los Angeles Times • Feb. 22, 2026

Other links connected to the hashtag were of the news clips.

From "All American Boys" by Jason Reynolds