A sweater is a knitted garment you pull over your head or button up the front to keep warm. Sweaters are made from yarn, usually wool, cotton, or synthetic fibers, and they trap air close to your body to insulate you against cold weather.

Today, we wear them for warmth and style.

Sweaters come in many styles. A pullover slides over your head, while a cardigan opens in the front with buttons or a zipper. Your grandmother might knit you a sweater by hand, looping yarn together row by row with knitting needles, or you might buy one from a store where it was made by machine.

Some sweaters feature patterns like stripes, Fair Isle designs, or cable knit textures that look like twisted ropes. An ugly Christmas sweater is decorated with intentionally ridiculous holiday designs and worn as a joke at parties. When you outgrow a favorite sweater, it might feel like saying goodbye to an old friend.