Sod or turf is grass and the part of the soil beneath it held together by the roots, or a piece of thin material.
In British English such material is more usually known as turf, and the word "sod" is limited mainly to agricultural senses (for example for turf when ploughed).
Sod is typically used for lawns, golf courses, and sports stadiums around the world. In residential construction, it is sold to landscapers, home builders or home owners who use it to establish a lawn quickly and avoid soil erosion. Sod can be used to repair a small area of lawn, golf course, or athletic field that has died. Sod is also effective in increasing cooling, improving air and water quality, and assisting in flood prevention by draining water.
Scandinavia has a long history of employing sod roofing and a traditional house type is the Icelandic turf house.
Following passage of the Homestead Act by the US Congress in 1862, settlers in the Great Plains used sod bricks to build entire sod houses. While it might be hard for some to imagine sod as a suitable primary building material, the prairie sod of the Great Plains was so dense and difficult to cut it earned the nickname Nebraska marble. Blacksmith John Deere made his fortune when he became the first to make a plow that could reliably cut the prairie sod.