Source : Webster's Revised Unabridged Dictionary (1913)

Sweven \Swe"ven\, n. [AS. swefen sleep, dream; akin to swebban,
   swefian, to put to sleep, to kill. [root]176. See
   {Somnolent}.]
   A vision seen in sleep; a dream. [Obs.] --Wycliff (Acts ii.
   17).

         I defy both sweven and dream.            --Chaucer.