A dinghy is generally either a small craft carried aboard a larger ship for the purpose of going ashore, or a small sailing boat, rowboat, or motorboat that may be used alone. Often a dinghy is defined by its size and is no larger than approximately, 19.5 feet (about 6m) long. Generally a smaller dinghy is preferable. Most commonly, a dingy is about 14 feet (4.26m) long.

The purpose of a dinghy as used aboard a larger watercraft is to transport people on a yacht or larger ship to shore, for either a long or short duration. The 14-foot dinghy is often carried on personal yachts, since this size is ideal for taking a family and provisions ashore, or for returning them to a ship. As well, a dinghy may be used for rescue purposes aboard large cruise ships. Though larger boats called lifeboats are usually preferred since they can carry larger groups of people.

Generally, the main boat, in order to maintain maximum space onboard a relatively small watercraft, tows the dinghy. Dinghies are usually coated with special resin, which keeps them from deteriorating due to constant exposure to water.

A dinghy may feature different types of propulsion. It may have a small motor that allows for quick transport, or it may simply have oars for rowing ashore. On larger crafts, a larger dinghy tends to have a motor.

The individual dinghy that is not towed may be a sailboat, motorboat or rowboat. Dinghy sailing has become a popular sport, and dinghy races are now quite common. While sailing for pleasure was once the province of the upper classes, small dinghy sailboats may be relatively inexpensive. It is not uncommon for people with slightly less means to be able to afford an inexpensive dinghy. The high performance dinghy for racing may, however, be much more expensive.

In other usage, dinghy may refer to a car pulled behind a motor home. The car functions on land, much as the dinghy functions on sea.