Stepwells (also known as vav or baori) are wells, cisterns or ponds with a long corridor of steps that descend to the water level. Stepwells played a significant role in defining subterranean architecture in western India from the 7th to the 19th century. Some stepwells are multi-storeyed and can be accessed by a Persian wheel which is pulled by a bull to bring water to the first or second floor. They are most common in western India and are also found in the other more arid regions of the Indian subcontinent, extending into Pakistan. The construction of stepwells is mainly utilitarian, though they may include embellishments of architectural significance, and may be temple tanks.

Stepwells are examples of the many types of storage and irrigation tanks that were developed in India, mainly to cope with seasonal fluctuations in water availability. A basic difference between stepwells on one hand, and tanks and wells on the other, is that stepwells make it easier for people to reach the groundwater and to maintain and manage the well.

The builders dug deep trenches into the earth for dependable, year-round groundwater. They lined the walls of these trenches with blocks of stone, without mortar, and created stairs leading down to the water. This led to the building of some significant ornamental and architectural features, often associated with dwellings in urban areas. It also ensured their survival as monuments.

A stepwell structure consists of two sections: a vertical shaft from which water is drawn and the surrounding inclined subterranean passageways and the chambers and steps which provide access to the well. The galleries and chambers surrounding these wells were often carved profusely with elaborate detail and became cool, quiet retreats during the hot summers.

A number of distinct names, sometimes local, exist for stepwells. In Hindi-speaking regions, they include names based on baudi (including bawdi (Rajasthani: बावड़ी), bawri, bawari, baori, baoli, bavadi and bavdi). In Gujarati and Marwari language, they are usually called vav, vavri or vaav (Gujarati: વાવ). Other names include kalyani or pushkarani (Kannada), baoli (Hindi: बावली), barav (Marathi: बारव) and degeenar (Bhojpuri: 𑂙𑂵𑂏𑂲𑂢𑂰𑂩).^{[citation needed]}

The stepwell may have originated during periods of drought to ensure enough access to the water. The earliest archaeological evidence of stepwells is found at Dholavira where the site also has water tanks or reservoirs with flights of steps. Mohenjo Daro's great bath is also provided with steps on opposite directions. Ashokan inscriptions mention construction of stepwells along major Indian roads at a distance of every 8 kos (about 20.8 miles or 33.5 km) for the convenience of travellers, but Ashoka states that it was a well-established practice which predated him and was done by former kings as well.

King Devanampriya Priyadarsin speaks thus. On the roads banyan-trees were caused to be planted by me, (in order that) they might afford shade to cattle and men, (and) mango-groves were caused to be planted. And (at intervals) of eight kos wells were caused to be dug by me, and flights of steps (for descending into the water) were caused to be built. Numerous drinking-places were caused to be established by me, here and there, for the enjoyment of cattle and men. [But] this so-called enjoyment (is) [of little consequence]. For with various comforts have the people been blessed both by former kings and by myself. But by me this has been done for the following purpose: that they might conform to that practice of morality.

— Ashokan Pillar Edict No 7