tholobate

thumb|upright=1.2|Dome upon tholobate of the Pennsylvania State Capitol, Harrisburg

A tholobate (), also called a drum or tambour, is the upright part of a building on which a dome is raised. It is generally in the shape of a cylinder or a polygonal prism. The name derives from the tholos, the Greek term for a round building with a roof and a circular wall. Another architectural meaning of drum is a circular section of a column shaft.