A form of truss, which has the principal rafters curving into the wall. In a raised cruck, the principal rafters start about halfway up the wall. (as opposed to on the ground) A jointed cruck is where two straight timbers are joined to make the angle between wall and roof slope.

Primitive truss formed by two main timbers, usually curved, set up as an arch or inverted V. Each half of the cruck is called a blade, and a pair is often cut from the same tree.

In architecture, particularly in England, a cruck is a curved timber, one of a pair, which supports the roof of a building.