Pur′lin.
(Carpentry.) A horizontal timber resting on a principal rafter, or a purlin-post, which is stepped into the ticbeam, and helps support the rafters of the roof. (See King-post truss.) In the cut:— a, principal rafter. b, purlin. c, common rafter. d, sheathing or slate-boarding. Purlins are also known as side-timbers or sidewavers.