The Collaborative International Dictionary of English v.0.48:

Sley \Sley\, n. [AS. sl?, fr. sle['a]n to strike. See Slay, v.
   t.]
   1. A weaver's reed. [Spelt also slaie.]
      [1913 Webster]

   2. A guideway in a knitting machine. --Knight.
      [1913 Webster]

   3. (Weaving) The number of ends per inch in the cloth,
      provided each dent in the reed in which it was made
      contained an equal number of ends. --E. Whitworth.
      [Webster 1913 Suppl.]

The Collaborative International Dictionary of English v.0.48:

Slaie \Slaie\, n. [See Sley.]
   A weaver's reed; a sley.
   [1913 Webster]