To recheck means to examine or verify something a second time to make sure you got it right the first time. When you finish a math test early, your teacher might encourage you to recheck your work before turning it in. When a scientist gets surprising results from an experiment, she'll recheck her measurements and calculations to confirm they're accurate.

The “re-” prefix tells you this is about doing something again. You might recheck your backpack before leaving for school to make sure you packed your homework. A pilot rechecks the airplane's instruments before takeoff. A proofreader rechecks an article for spelling errors even after reading it carefully once.

Rechecking catches mistakes you might have missed the first time. Sometimes when you're focused on finishing something quickly, small errors slip by. A fresh look helps you spot them. It's also smart to recheck when something seems wrong or confusing, like if your answer to a word problem doesn't make sense, or when the stakes are high enough that being wrong would cause real problems.