WordNet (r) 3.0 (2006):

categorisation
    n 1: a group of people or things arranged by class or category
         [syn: classification, categorization, categorisation]
    2: the basic cognitive process of arranging into classes or
       categories [syn: classification, categorization,
       categorisation, sorting]
    3: the act of distributing things into classes or categories of
       the same type [syn: categorization, categorisation,
       classification, compartmentalization,
       compartmentalisation, assortment]