The Collaborative International Dictionary of English v.0.48:

Sise \Sise\, n. [From Assize.]
   An assize. [Obs.]
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Sise \Sise\, n. [See Sice.]
   Six; the highest number on a die; the cast of six in throwing
   dice.
   [1913 Webster]

         In the new casting of a die, when ace is on the top,
         sise must needs be at the bottom.        --Fuller.
   [1913 Webster]

WordNet (r) 3.0 (2006):

sise
    n 1: the cardinal number that is the sum of five and one [syn:
         six, 6, VI, sixer, sise, Captain Hicks, half a
         dozen, sextet, sestet, sextuplet, hexad]