Aristotle's Categories and Topics
This contribution is based on Aristotle's Categories and Topics (using of synonyms).
The first using
That which is not subordinate to something else is used synonymously with it. For example man and bull are both animals, because the definitions of them are identical. According to the classical definition (Aristotle's Categories) the differentiae between animal and knowledge are different in kind. One sort of knowledge does not differ from another by being twofooted while twofooted is one of a possible differentiae of the genus Animal.
The second using
Bird and winged twofooted animal are subordinate one to the other but both are actually the synonyms.
"...in speaking of animal one takes in more than in speaking of man." This implies that man and animal are subordinated one to the other and the argument in the first sentence of the first section is denied. (If Aristotle had not used both man and bull as the examples of only animals, the rational would have not had to be mixed with irrational instead of recognising them as subordinated one to the other. See w:Porphyrian tree.)
- Chapter 5 of Aristotle's Categories translated by J. L. Ackrill.