Latin term probably derived from [varus] meaning "bent or crooked". The term is used in medicine to denote a single dilation of a vein. The plural form of [varix] is [varices], the adjective [varicose] denotes an area affected by varices.

Peripheral varicose veins are usually caused by failure of the venous valves found in them.

Note that the dilation of a vein is called a varix, while the dilation of an artery is called an aneurysm.