"Beam and stringer" and "post and timber" are designations for the cross sectional dimensions of heavy timber memebers. A "beam and stringer" cross section has a depth that is more than 2 inches greater than its width. The piece is expected to be used mainly in bending. A "post and timber" cross section has its depth within 2 inches of its width. It is primarily intended for use in compression. The grading standards vary for the two designations, hence the design values also differ.