categorize v.

1580s, in Aristotle's logic, "a highest notion," from French catégorie, from Late Latin categoria, from Greek katēgoria "accusation, prediction, category," verbal noun from katēgorein "speak against; to accuse, assert, predicate," from kata "down to" (or perhaps "against;" see cata-) + agoreuein "to harangue, to declaim (in the assembly)," from agora "public assembly" (from PIE root *ger- "to gather").

The Greek verb's original sense of "accuse" had weakened to "assert, name" by the time Aristotle applied katēgoria to his 10 classes of "expressions that are in no way composite," perhaps "things that can be named simply." Precisely what he meant by it "has been disputed almost from his own day till the present" [OED].

What, exactly, is meant by the word "category," whether in Aristotle or in Kant and Hegel, I must confess that I have never been able to understand. I do not myself believe that the term "category" is in any way useful in philosophy, as representing any clear idea. [Bertrand Russell, "A History of Western Philosophy," 1945]

The sense of "any very wide and distinctive class, any comprehensive of persons or things" is from 1660s.

category should be used by no-one who is not prepared to state (1) that he does not mean class, & (2) that he knows the difference between the two .... [Fowler]

word-forming element used to make verbs, Middle English -isen, from Old French -iser/-izer, from Late Latin -izare, from Greek -izein, a verb-forming element denoting the doing of the noun or adjective to which it is attached.

The variation of -ize and -ise began in Old French and Middle English, perhaps aided by a few words (such as surprise, see below) where the ending is French or Latin, not Greek. With the classical revival, English partially reverted to the correct Greek -z- spelling from late 16c. But the 1694 edition of the authoritative French Academy dictionary standardized the spellings as -s-, which influenced English.

In Britain, despite the opposition to it (at least formerly) of OED, Encyclopaedia Britannica, the Times of London, and Fowler, -ise remains dominant. Fowler thinks this is to avoid the difficulty of remembering the short list of common words not from Greek which must be spelled with an -s- (such as advertise, devise, surprise). American English has always favored -ize. The spelling variation involves about 200 English verbs.

also categorisation, "act or process of placing in a catalogue or list," by 1866, noun of action from categorize. Perhaps influenced by French catégorisation (1845).