The Collaborative International Dictionary of English v.0.48:

Scythe \Scythe\ (s[imac]th), n. [OE. sithe, AS. s[imac][eth]e,
   sig[eth]e; akin to Icel. sig[eth]r a sickle, LG. segd, seged,
   seed, seid, OHG. segansa sickle, scythe, G. sense scythe, and
   to E. saw a cutting instrument. See Saw.] [Written also
   sithe and sythe.]
   1. An instrument for mowing grass, grain, or the like, by
      hand, composed of a long, curving blade, with a sharp
      edge, made fast to a long handle, called a snath, which is
      bent into a form convenient for use.
      [1913 Webster]

            The sharp-edged scythe shears up the spiring grass.
                                                  --Drayton.
      [1913 Webster]

            Whatever thing
            The scythe of Time mows down.         --Milton.
      [1913 Webster]

   2. (Antiq.) A scythe-shaped blade attached to ancient war
      chariots.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Syth \Syth\, Sythe \Sythe\, prep., adv., conj. & n.
   See Sith, Sithe. [Obs.] --Chaucer. --Piers Plowman.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Sythe \Sythe\, n.
   Scythe. [Obs. or R.]
   [1913 Webster]