(n)the boundary between Maryland and Pennsylvania; symbolic dividing line between North and South before the American Civil War, Syn.Mason and Dixon line, Mason and Dixon's line
(n)mechanical system in a factory whereby an article is conveyed through sites at which successive operations are performed on it, Syn.line, assembly line
(n)secretive snake of city dumps and parks as well as prairies and open woods; feeds on earthworms; of central United States, Syn.Tropidoclonion lineatum