To curtail something means to reduce, limit, or cut it short. When a school curtails recess because of bad weather, students get less time to play outside than usual. When a family curtails their vacation plans due to unexpected expenses, they might take a shorter trip or visit fewer places than they originally intended.

The word suggests deliberately making something smaller or briefer than it was or was going to be. A coach might curtail practice when players are exhausted. A principal might curtail a long-winded assembly speaker who's gone over time. Parents might curtail their children's screen time during the school week.

Curtail often appears when talking about rights, freedoms, or activities. A new rule might curtail students' ability to use phones during lunch. Bad weather might curtail outdoor activities. Budget cuts might curtail a library's hours or programs.

When you curtail something, you're not eliminating it entirely, just reducing its size, scope, or duration. You're making it less than it was or less than it could have been.