The Collaborative International Dictionary of English v.0.48:

capitalisation \capitalisation\ n.
   1. same as capitalization.

   Syn: capitalization.
        [WordNet 1.5 +PJC]

WordNet (r) 3.0 (2006):

capitalisation
    n 1: writing in capital letters [syn: capitalization,
         capitalisation]
    2: an estimation of the value of a business [syn:
       capitalization, capitalisation]
    3: the act of capitalizing on an opportunity [syn:
       capitalization, capitalisation]
    4: the sale of capital stock [syn: capitalization,
       capitalisation]