Word of the Day:

: a word or phrase preceded by the symbol # that classifies or categorizes the accompanying text (such as a tweet)

Jessica used the hashtag #parenting to share ideas, advice, and stories with other moms online.

"On Twitter, the #blessed hashtag may still prompt some genuine sentiment ("blessed to have such a supportive family behind me") but more often than not it is blatantly self-promotional ("#blessed to be in 3rd place at the Webbys... please vote now!"), surreptitiously braggy, or just plain absurd (Tim Tebow's Twitter bio is just the single word)." - Jessica Bennett, New York Times, May 2, 2014

More example sentences

Social media has made the hashtag a ubiquitous part of Internet culture, starting with Twitter and expanding to other sites. Originally designed for categorizing posts, the hashtag can now be a tool for a supplementary coy or witty comment (e.g., #awkward). The word "tag" can mean "a word or phrase used for description or identification." "Hash" is short for "hash mark," a term for what we more commonly call a pound sign (and, less commonly, an octothorp). The "hash" in "hash mark" is probably an alteration of "hatch," a term for the crisscrossing of lines (as when adding shading to a drawing).