- Purlin is a support board of a roof.
An example of a purlin is a horizontal wooden board holding up the rafters of a roof.
purlin definition by Webster's New World
Webster's New World College Dictionary Copyright © 2010 by Wiley Publishing, Inc., Cleveland, Ohio. Used by arrangement with John Wiley & Sons, Inc.
a horizontal timber supporting the rafters of a roof
Origin: Middle English purlyn ; from uncertain or unknown; perhaps
purlin definition by American Heritage Dictionary
One of several horizontal timbers supporting the rafters of a roof.
Origin: Middle English.