indexing vs categorisation

indexing and categorisation both are nouns.

Word	Noun	Adjective	Verb	Adverb
indexing	Yes	No	No	No
categorisation	Yes	No	No	No

As nouns, categorisation is a hypernym of indexing; that is, categorisation is a word with a broader meaning than indexing:

indexing: the act of classifying and providing an index in order to make items easier to retrieve
categorisation: the act of distributing things into classes or categories of the same type

indexing (noun)	categorisation (noun)
the act of classifying and providing an index in order to make items easier to retrieve	the act of distributing things into classes or categories of the same type
	the basic cognitive process of arranging into classes or categories
	a group of people or things arranged by class or category