A feather is one of the light, flat structures that covers a bird's body and enables flight. Each feather has a stiff central shaft with hundreds of thin strands called barbs branching off on either side, creating a smooth, flexible surface. When you find a feather on the ground, you can run your finger along it and feel how the barbs zip back together, almost like natural Velcro.

Feathers serve multiple purposes for birds. Flight feathers on the wings and tail provide the lift and control needed for flying. Smaller feathers covering the body keep birds warm, like a built-in winter coat. Some birds have brilliantly colored feathers for attracting mates, like the peacock's stunning tail display. Feathers are so light that people use the phrase light as a feather to describe something that weighs almost nothing.

The word also appears in expressions: to ruffle someone's feathers means to annoy them, while a feather in your cap refers to an achievement you can be proud of. When you're feeling happy and energetic, you might be in fine feather, like a bird with healthy, glossy plumage ready to take flight.