The ovin is an agricultural building designed for drying sheaves before threshing. It typically consisted of a pit with a stove without a chimney and an upper tier for stacking sheaves. According to popular beliefs, the ovin is inhabited by the ovinik. Such structures were built in regions with a low number of sunny days, for example, in central and northern Russia and Belarus.

Ovins could be log-built, woven, plastered, dug, beaten, clay, and rarely stone.

The main parts of the ovin include a pit or pit house, where a fire is lit, usually directly, less often in a smoky stove. Above the pit is the drying area, where sheaves are placed on grates: either in a single row, with the ears on the grates, or mixed, with the butts up and down. Sheaves enter the drying area through the hayloft or front room, which in the barn can be more spacious and used for threshing and winnowing. The ovin or grates are covered with a layer of earth and thatched with straw. One can enter the pit house from the outside through a crawl space or underpass, which are sometimes also thatched or dug.

A structure that combines the functions of an ovin and a threshing floor for grain threshing is called a gumno.