A raincoat is a waterproof or water-resistant garment worn on the upper body to shield the wearer from rain. The term rain jacket is sometimes used to refer to raincoats with long sleeves that are waist-length. A rain jacket may be combined with a pair of rain pants to make a rainsuit. Rain clothing may also be in one piece, like a boilersuit. Raincoats, like rain ponchos, offer the wearer hands-free protection from the rain and elements; unlike the umbrella.

Waterproofing is the process of making an object, person or structure waterproof or water-resistant so that it remains relatively unaffected by water or resisting the ingress of water under specified conditions. Such items may be used in wet environments or underwater to specified depths.