A badge is a small marker shown beside something else to call attention to a count or status. It is like a tiny flag attached to a folder so you can spot an update quickly.
For example, an inbox icon might have a badge showing that new messages are waiting. A badge can also say “New” or show a small number. It should add a useful detail without taking over the page.
Keep its meaning easy to understand. If color is used to show a warning or status, add a word or symbol too, so the meaning is not carried by color alone.