Categories

"Things are said to be named 'equivocally' when, though they have a
common name, the definition corresponding with the name differs for each. Thus,
a real man and a figure in a picture can both lay claim to the name 'animal';
yet these are equivocally so named, for, though they have a common name, the
definition corresponding with the name differs for each. For should any one
define in what sense each is an animal, his definition in the one case will be
appropriate to that case only.

On the other hand, things are said to be named 'univocally' which have
both the name and the definition answering to the name in common. A man and an
ox are both 'animal', and these are univocally so named, inasmuch as not only
the name, but also the definition, is the same in both cases: for if a man
should state in what sense each is an animal, the statement in the one case
would be identical with that in the other.

Things are said to be named 'derivatively', which derive their name from
some other name, but differ from it in termination. Thus the grammarian derives
his name from the word 'grammar', and the courageous man from the word
'courage'."

- Excerpted from "Categories"