建筑(jiàn zhù) - building, architecture in Mandarin

建筑 (jiàn zhù) is a building as a structure, and also building and architecture as fields. 这座建筑 is that building over there, 建筑工人 is a construction worker, 建筑师 is an architect and 建筑学 is architecture as a university subject. Its measure word is 座, the one used for large fixed things.

Beside it sits 建 as a bare verb, to build, and 建立 for establishing something abstract such as a relationship or a system. 建筑 can also work as a verb meaning to construct, though in ordinary speech 盖 or 建 is far more natural for putting up a house.

The trap is that English building is a much humbler word than 建筑. A shed, a corner shop and a bungalow are 房子 or 楼, not 建筑; the Chinese word leans towards something substantial or architecturally notable. Calling your flat 一座建筑 sounds grand in a way you probably did not intend.