Bottoms are an apparel term used to describe the layers of clothing worn on the bottom half of the body. Bottoms may be in reference to undergarments or outerwear.
About Leggings:
Leggings are tight-fitting pants that extend from the waist to the ankles and are worm mostly for exercise or any other type of fitness activity. Leggings are typically made from stretchy and breathable materials such as nylon, polyester or a blend of lycra, and either nylon, cotton, or a cotton-polyester blend. Leggings may come in varying lengths, from knee-length and capri-length, all the way to full length pants.