The Collaborative International Dictionary of English v.0.48:

Graticule \Grat"i*cule\, n. [F. See Graticulation.]
   A design or draught which has been divided into squares, in
   order to reproduce it in other dimensions.
   [1913 Webster]

WordNet (r) 3.0 (2006):

graticule
    n 1: a network of fine lines, dots, cross hairs, or wires in the
         focal plane of the eyepiece of an optical instrument [syn:
         reticle, reticule, graticule]