Apparel is the term used to describe pieces of material that are crafted to be worn on the body. Apparel items include (but are not limited to): Tops, Bottoms, Skirts, Shorts, Sweaters, and Swimsuits.
About Pants:
Pants are apparel bottoms that have material which covers the entire leg, down to the ankle.
About Shorts:
Shorts are apparel bottoms that have material cut short above the knee or slightly below the knee.