A cupola is a small structure that protrudes up from the roof of a building, often with a pointy roof and windows or vents on the sides. The word "cupola" comes from the Latin word "cupula," which means "small cup". Cupolas were originally designed to add natural light and ventilation to the area under a roof. They were commonly seen on barns and big old buildings, churches, and places with big open spaces inside where heat and humidity can pose a problem. Cupolas can be found in many shapes, including square, round, and octagonal. They can be both functional and decorative, and they come in a variety of designs to match the architectural style of the building. Some popular cupola designs include Contemporary, Georgian, Classical, Victorian, and Colonial.

Cupolas were primarily functional originally, but they became a feature for adding beauty as their function was replaced with other new inventions. Cupolas were used to allow a continuous flow of air into the hayloft, helping to dry the hay. They also allowed natural light to brighten the dark reaches of a barns vaulted ceiling. Cupolas can be an attractive and functional addition to a roof that can serve as a skylight, a lookout, or both. They can be used to naturally ventilate a space and improve the visual appeal of the building it tops.