When things have only a name in common and the definition of being which corresponds to the name is different, they are called homonymous. Thus, for example, both a man and a picture are animals. These have a common name (for each of these is called animal), but the definition of being is different. For if one is to define the man, he will say he is a perceptive living substance, and the picture an imitation of a perceptive living substance.
When things have the name in common and the definition of being which corresponds to the name is the same, they are called synonymous. Thus, for example, both a man and an ox are animals. Each of these is called by a common name, ‘animal’, and the definition of being is also the same; for if one is to give the definition of each – what being an animal is for each of them – one will give the same definition. The same word, however, can possibly be both homonymous and synonymous as to another and different thing. Thus for the real man and picture the animal is homonymous, but for the man and ox synonymous.
When things have the definition of being which corresponds to the name the same and the name is different, they are called polyonymous, e.g. rapier, sword, saber. These have the same definition (for you may say for each it is a sharp weapon), but they do not have a common name.
When things have both the name and the definition of being which corresponds to the name different, they are called heteronymous, such as ascent and descent. These have a difference both in name and in definition. It should be noted that heterous is different from heteronymous; for things regarded in reference to one and the same subject but include a different name are heteronymous. For example, both ascent and descent are regarded on a ladder, and they have different definitions and names too. These, then, are called heteronymous. Heterous those that are entirely different, both in subject and in name, e.g. man, horse.
When things get their name from something, with a difference of ending, they are called paronymous. Thus, for example, the grammarian gets his name from grammar, the brave get theirs from bravery; for these have mainly nothing in common either in name or in definition, but they both commune and differ in some way on both sides (in name and definition). It needs, on paronymous, to be present these four conditions: communion of thing and difference of thing, communion of name and difference of ending; for if one of these is lacking, there will be no more paronymous.
Bibliography: Aristotle Categories, J. Philoponus in Aristotle’s Categ., J.L. Ackrill in Aristotle’s Categ.
Translation – text editing: George Kotsalis