Origin and history of subcategory

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, 1989].

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 class 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 of Latin origin meaning "under, beneath; behind; from under; resulting from further division," from Latin preposition sub "under, below, beneath, at the foot of," also "close to, up to, towards;" of time, "within, during;" figuratively "subject to, in the power of;" also "a little, somewhat" (as in sub-horridus "somewhat rough"), from PIE *(s)up- (perhaps representing *ex-upo-), a variant form of the root *upo "under," also "up from under," which also yielded Greek hypo- and English up.

The Latin word also was used in Latin as a prefix and in various combinations. In Latin it was reduced to su- before -s- and assimilated to following -c-, -f-, -g-, -p-, and often -r- and -m-.

In Old French the prefix appears in the full Latin form only "in learned adoptions of old Latin compounds" [OED], and in popular use it was represented by sous-, sou-; as in French souvenir from Latin subvenire, souscrire (Old French souzescrire) from subscribere, etc.

The original meaning is now obscure in many words from Latin (suggest, suspect, subject, etc.). The prefix is active in Modern English; the indication generally being:

1. "under, beneath, at the bottom of;" in adverbs "down, low, lower;"

2. "inferior part, agent, division, or degree; inferior, having subordinate position" (subcontractor) also forming official titles (subaltern);

It also can indicate "division into parts or sections;" "next below, near, close to" (subantarctic); "smaller" (sub-giant); and it may be used generally as "somewhat, partial, incomplete" (subliterate).