Source : Webster's Revised Unabridged Dictionary (1913)

Reef \Reef\, v. t. [imp. & p. p. {Reefed} (r[=e]ft); p. pr. &
   vb. n. {Reefing}.] (Naut.)
   To reduce the extent of (as a sail) by roiling or folding a
   certain portion of it and making it fast to the yard or spar.
   --Totten.

   {To reef the paddles}, to move the floats of a paddle wheel
      toward its center so that they will not dip so deeply.

Reefing \Reef"ing\, n. (Naut.)
   The process of taking in a reef.

   {Reefing bowsprit}, a bowsprit so rigged that it can easily
      be run in or shortened by sliding inboard, as in cutters.