English word hashtag comes from English Internet Relay Chat

Detailed word origin of hashtag

Dictionary entry	Language	Definition
Internet Relay Chat	English (eng)
hashtag	English (eng)	(Internet) A metadata tag, signaled by a preceding hash sign (#), used to label content. [from 2007]. (internet, informal) The hash sign itself. (Can we add an example for this sense?) (transitive, Internet) To label (a message) with a hashtag.

Words with the same origin as hashtag