Hash icon

When to use it

The # means one of several things by context — a hashtag, a chat channel, a number-of, or a code comment. Heroicons, Remix and Iconoir name it hashtag; the others call it hash. Because the glyph is overloaded, never rely on it alone to mean 'channel' the way Slack does unless your product has taught that convention; pair it with the channel name.

Reach for the hash when the label is a hashtag, a chat channel, or a numbered reference — '#general', '#design', 'issue #42'. It works because it's a literal character rather than a metaphor, but that also makes it context-dependent: the same glyph reads as 'topic tag' on social and 'room' in chat. Set expectations with the adjacent text, and don't use it to mean a content tag, where the tag icon is clearer.

• Reaching for Tag? Reach for the tag shape when you mean a metadata label on content, not a hashtag or channel.
• Reaching for Message? Reach for the speech bubble for the conversation itself rather than a single channel's marker.