King-post n. : A member of a common form of truss, as a roof truss. It is strictly a tie, intended to prevent the sagging of the tiebeam in the middle. If there are struts, supporting the main rafters, they often bear upon the foot of the king-post. Called also crown-post.

Example:
12 X 12 shed (12 inch king post-not much of a pitch)-how many bundles of shingles?

Taxonomy
king post, truss, post truss, the apex, queen, roof, free encyclopedia, tie beam, roof truss, crown post, central post, collar beam, Queen post, truss bridge, wood, horizontal beam, wing, nave roof.

Defination from the web:
king post to support the roof ridge. ... DFE Ascender III-C ultralight aircraft showing its king post above the wing. ...