Roof
the external covering on the top of a building; sometimes of stone, but usually of wood overlaid with slates, tiles, lead, etc. The form and construction of the timber work of roofs differ materially according to the nature of the building on which it is to be placed, and any attempt to notice all the varieties would far exceed the limits of this work.
The main parts of the framing, which in most cases are placed at regular intervals, are each called a truss, principal, or pair of principals; these, in ornamental open roofs, are the leading features, and in some ancient roofs are contrived with an especial view to appearance. A king-post roof has one vertical post in each truss, a queen-post roof has two. Since the introduction of iron in the construction of roofs, spaces of almost any width can be roofed over.
Also that which resembles, or corresponds with, the cover of a building; as, the roof of the mouth, the roof of the firmament, etc.