Breath is the air that moves in and out of your lungs when you breathe. Every few seconds, without even thinking about it, you take a breath in and let a breath out. Your body needs the oxygen in each breath to power your muscles and brain.

You can feel your breath when you hold your hand in front of your mouth and exhale, or when you see it make little clouds on a cold morning. Athletes learn to control their breathing during races. Musicians who play instruments like the flute or trumpet need strong breath control to create beautiful sounds. Swimmers practice holding their breath underwater.

The word appears in many common expressions. When something exciting or scary happens, it might take your breath away or leave you breathless. After running hard, you need to catch your breath and let your breathing return to normal. If you're nervous before performing, someone might tell you to take a deep breath to calm down. When you speak under your breath, you're whispering so quietly that others can barely hear you.

A breath can also mean a tiny amount of something, like when there's just a breath of wind moving through the trees, barely enough to rustle the leaves.