Warning

Heads up, not house on fire. It is the general-danger sign: the triangle says “careful”, and the words next to it say what about. The UK Health and Safety Executive's workplace guide, as of 2026, still labels it “General danger”. One ⚠️ before a note sounds like a clipboard: “⚠️ Don't share logins.” Stack three and it means don't skim this.

Where did the warning triangle come from?

From European road signs, then safety manuals. Early road signs marked hazards with a plain hollow triangle or a vertical bar. At a 1931 traffic-sign meeting, a delegate proposed the exclamation triangle for temporary or general dangers such as road repairs. At a 1949 conference, France defended its vertical-bar version, but the chair recorded majority support for the exclamation sign as “other danger”, with a small panel naming the risk. A 1998 proposal to Unicode, the standard that gives characters their computer codes, noted it in printed safety notes and product manuals.

Someone sent you just ⚠️ — what do they want?

They want you to slow down before you react. Alone, it usually means “check this first”, so read it against the message right before it. On a link, it means “open carefully”, not “I checked this”.

Fired back bare with no words, it stops sounding helpful and starts sounding judgy, as if you are the problem. In a tense thread, say what's wrong instead.