Webster's Revised Unabridged Dictionary · 1913

Hammer-beam

Hammer-beam (-bēm`) , noun

(Gothic Architecture) A member of one description of roof truss, called hammer-beam truss, which is so framed as not to have a tiebeam at the top of the wall. Each principal has two hammer-beams, which occupy the situation, and to some extent serve the purpose, of a tiebeam.