An umbrella or parasol is a folding canopy supported by wooden or metal ribs that is usually mounted on a wooden, metal, or plastic pole. It is designed to protect a person against rain or sunlight. The term umbrella is traditionally used when protecting oneself from rain, with parasol used when protecting oneself from sunlight, though the terms continue to be used interchangeably. Often the difference is the material used for the canopy; some parasols are not waterproof, and some umbrellas are transparent. Umbrella canopies may be made of fabric or flexible plastic. There are also combinations of parasol and umbrella that are called en-tout-cas (French for "in any case").

Umbrellas and parasols are primarily hand-held portable devices sized for personal use. The largest hand-portable umbrellas are golf umbrellas. Umbrellas can be divided into two categories: fully collapsible umbrellas, in which the metal pole supporting the canopy retracts, making the umbrella small enough to fit in a handbag, and non-collapsible umbrellas, in which the support pole cannot retract and only the canopy can be collapsed. Another distinction can be made between manually operated umbrellas and spring-loaded automatic umbrellas, which spring open at the press of a button.

Hand-held umbrellas have a type of handle which can be made from wood, a plastic cylinder or a bent "crook" handle (like the handle of a cane). Umbrellas are available in a range of price and quality points, ranging from inexpensive, modest quality models sold at discount stores to expensive, finely made, designer-labeled models. Larger parasols capable of blocking the sun for several people are often used as fixed or semi-fixed devices, used with patio tables or other outdoor furniture, or as points of shade on a sunny beach.

Parasol may also be called sunshade, or beach umbrella (US English). An umbrella may also be called a brolly (UK slang), parapluie (nineteenth century, French origin), rainshade, gamp (British, informal, dated), or bumbershoot (rare, facetious American slang). When used for snow, it is called a paraneige.