To tuck means to push, fold, or arrange something into a neat, secure position, often by tucking it under or into something else. When you tuck in your shirt, you push the bottom edge inside your pants or skirt so it stays smooth and doesn't hang out. At bedtime, someone might tuck you in by pulling your blankets snugly around you and tucking the edges under the mattress.

The word captures that combination of folding and securing. You might tuck a napkin under your plate, tuck a pencil behind your ear, or tuck your knees up to your chest when sitting. Birds tuck their heads under their wings to sleep.

As a noun, a tuck is a tucked position or fold. A gymnast does a tuck by pulling their knees tight against their chest while flipping through the air.

The action usually makes things tidier, safer, or more compact. When you tuck away your allowance in a drawer, you're putting it somewhere safe and out of sight. A chef might tuck fresh herbs into a roasted chicken. The word suggests both the physical motion of folding or pushing something into place and the result: something snug, protected, and neatly arranged.