Source : Webster's Revised Unabridged Dictionary (1913)

Lintel \Lin"tel\ (l[i^]n"t[e^]l), n. [OF. lintel, F. linteau,
   LL. lintellus, for limitellus, a dim. fr. L. limes limit. See
   {Limit}.] (Arch.)
   A horizontal member spanning an opening, and carrying the
   superincumbent weight by means of its strength in resisting
   crosswise fracture.

Source : WordNet®

lintel
     n : horizontal beam used as a finishing piece over a door or
         window [syn: {header}]