A bracket is a category or range that groups similar things together. When teachers organize students into reading brackets, they're grouping kids who read at similar levels. Tax brackets group people who earn similar amounts of money so they pay taxes at the same rate. In sports tournaments, brackets show who plays against whom in each round.

The word also refers to the physical marks used to show these groupings: the curved or angled marks [ ] or { } that connect related items on paper. Tournament brackets look like trees lying on their sides, with lines branching out to show which teams face each other. As players win, they advance through the bracket until someone reaches the championship.

A bracket can also be a support that holds something up or attaches it to a wall, like the metal brackets holding up a bookshelf.

When you bracket something, you're either grouping it with similar things or setting it apart for special attention. A scientist might bracket certain data to analyze it separately. People also use the phrase in the same bracket to mean roughly equal or similar, like saying two runners finished in the same time bracket.