Source : Webster's Revised Unabridged Dictionary (1913)

Rafter \Raft"er\, n.
   A raftsman.

Rafter \Raft"er\, n. [AS. r[ae]fter; akin to E. raft, n. See
   {Raft}.] (Arch.)
   Originally, any rough and somewhat heavy piece of timber.
   Now, commonly, one of the timbers of a roof which are put on
   sloping, according to the inclination of the roof. See
   Illust. of {Queen-post}.

         [Courtesy] oft is sooner found in lowly sheds, With
         smoky rafters, than in tapestry halls.   --Milton.

Rafter \Raft"er\, v. t.
   1. To make into rafters, as timber.

   2. To furnish with rafters, as a house.

   3. (Agric.) To plow so as to turn the grass side of each
      furrow upon an unplowed ridge; to ridge. [Eng.]

Source : WordNet®

rafter
     n 1: one of several parallel sloping beams that support a roof
          [syn: {balk}, {baulk}]
     2: someone who travels by raft [syn: {raftsman}, {raftman}]
     v : provide (a ceiling) with rafters