Source : Webster's Revised Unabridged Dictionary (1913)

Ret \Ret\, v. t.
   See {Aret}. [Obs.] --Chaucer.

Ret \Ret\, v. t. [Akin to rot.]
   To prepare for use, as flax, by separating the fibers from
   the woody part by process of soaking, macerating, and other
   treatment. --Ure.

Source : WordNet®

ret
     v : of flax, hemp, or jute, so as to promote loosening of the
         fibers form the woody tissue
     [also: {retting}, {retted}]