Categories, Section 1, Part 1

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'.