in masonry construction, any of the horizontal, wood or metal pieces which support the floor planks of a scaffold and which are themselves supported at one end in holes left temporarily in a wall under construction
See putlog in American Heritage Dictionary 4
(po͝otˈlôgˌ, -lŏgˌ, pŭtˈ-)
noun
One of the short pieces of lumber supporting the floor of a scaffold.