The adjective forms for the verb to classify are the present participle, classifying (a classifying factor), and the past participle, classified (a classified ad).
A related adjective form is classifiable.
Synonyms for the word classified are confidential, top-secret, private, and restricted. Some antonyms for classified are open, public, and unconcealed.
categorization, taxonomy
classifies
In my opinion categorization would be the best.
rule :) A+
Remonstrations
counting
forever
blood
Cow.
orbit
w
Counting
I'd suggest the word "ratio"
A thesaurus.