CATEGORIES.

Homonyms are things that share only a name, while the definition of essence corresponding to the name is different. For example, both a human and a painted figure are called "animal." Their name is common, but the definition of their essence is different. If one were to define what it means to be an animal for each of them, one would provide a unique definition for each. Synonyms are things that have both the name and the definition of essence in common, such as a human and an ox. Both a human and an ox are called by the common name "animal," and the definition of their essence is the same. Paronyms are things that get their name from another, differing by a grammatical ending, such as "grammarian" from "grammar" or "courageous" from "courage."

2 Of things said, some are said in a combination, others without combination. Those in combination are, for example, "a human runs" or "a human wins." Those without combination are, for example, "human," "ox," "runs," "wins."

3 Of existing things, some are predicated of a subject but are not in any subject. For example, "human" is predicated of an individual human, but is not in a subject. Others are in a subject, but are not predicated of any subject. (By "in a subject," I mean what is in something not as a part and cannot exist separately from that in which it is). For example, a particular instance of grammatical knowledge is in a subject—the soul—but is not predicated of any subject. Likewise, a particular white thing is in a subject—the body (for every color is in a body)—but is not predicated of any subject.

Others are both predicated of a subject and are in a subject, such as "knowledge," which is in a subject—the soul—and is predicated of "grammar." Others are neither in a subject nor predicated of any subject, such as a particular human or a particular horse; for none of these are in a subject nor are they predicated of a subject. Simply put, individual things and those that are one in number are not predicated of any subject, though nothing prevents some of them from being in a subject. For a particular instance of grammar is in a subject, but it is not predicated of any subject.

Whenever one thing is predicated of another as its subject, everything that is said of the predicate will also be said of the subject. For example, "human" is predicated of an individual human, and "animal" is predicated of "human." Therefore, "animal" will also be predicated of the individual human. For that individual human is both a human and an animal.

Of different kinds that are not ordered under one another, their species and differences are also different, such as for "animal" and "knowledge." For the differences of "animal" are "footed," "two-footed," "winged," and "aquatic," but none of these apply to "knowledge." For knowledge does not differ from knowledge by being two-footed. But for kinds that are ordered under one another, nothing prevents them from having the same differences. For the higher kinds are predicated of those below them, so that as many differences as the predicate has, the subject will also have.

4 Of things said without any combination, each signifies either substance, quantity, quality, relation, place, time, position, state, acting, or being affected. Substance is, to speak roughly, "human" or "horse." Quantity is "two cubits" or "three cubits." Quality is "white" or "grammatical."