Play or pause button

It's the one key that switches between playing and pausing. You know it from remote controls, earbuds, car stereos and the media keys above a laptop keyboard: one press starts playback, the next press pauses it, and the same press resumes. The emoji simply glues the two familiar marks together, ▶ for play and ‖ for pause. Stop, the square, is a different button that ends playback rather than holding it.

The marks are older than any screen. They appeared on reel-to-reel and cassette recorders from the 1960s and were later fixed as standard graphical symbols for equipment, which is why a Japanese remote and a Brazilian car radio use the same shapes. The triangle is usually explained as pointing the way the tape ran, so a left-pointing triangle meant rewind. Because the symbols live on hardware, people everywhere read them without a word of explanation, and when hardware makers started putting both functions on one button, the combined picture followed.

What does ⏯️ mean when someone sends it?

Usually "here's something to play", or a light "pause" or "resume". It is a practical emoji, not an emotional one. Next to a link it says the link is a song, video, podcast or episode. In a post about a live stream or a playlist it works as a "now playing" label. Headphone or music emoji around it push the reading towards listening.

Away from media it turns into a joke about the conversation itself: "let's ⏯️ this tomorrow" means put the discussion on hold, and a lone ⏯️ after a long silence can mean "picking up where we left off". It never carries a mood on its own; the words around it decide whether it means start, hold or continue.