जमीनीखालील पाणी काढण्यासाठी केलेल्या खड्ड्यावजा बांधकामास विहीर असे म्हणतात. विहिरीतील पाणी विद्युत् उपकरण वा मनुष्यबळ लावून काढले जाते आणि घरगुती वापरासाठी तसेच सिंचनासाठी वापरले जाते. विहिरीचे अन्य प्रयोग विश्व मध्ये काही जागी पेट्रोल आणि गैस विहीरी पण आहेत.येथे ज़मीनीची खुदाई करून कई लाख क्यूबिक मीटर गैसचे प्रतिदिन उत्पादन केले जाते.

A well is an excavation or structure created in the earth by digging, driving, or drilling to access liquid resources, usually water. The oldest and most common kind of well is a water well, to access groundwater in underground aquifers. The well water is drawn up by a pump, or using containers, such as buckets or large water bags that are raised mechanically or by hand. Water can also be injected back into the aquifer through the well. Wells were first constructed at least eight thousand years ago and historically vary in construction from a simple scoop in the sediment of a dry watercourse to the qanats of Iran, and the stepwells and sakiehs of India. Placing a lining in the well shaft helps create stability, and linings of wood or wickerwork date back at least as far as the Iron Age.