An important fragment of the lost portion of Aristotle's Poetics is the definition of synonyms preserved by Simplicius, which corresponds to Aristotle's own citation of the Poetics for synonyms in the Rhetoric, 3. 2.1404b 37 ff. I shall argue elsewhere that this derives from a discussion of the sources of verbal humour in the lost account of comedy and humour. Here it is my aim to show that Simplicius definitely derived the quotation from Porphyry, which pushes back the attestation of (...) this part of the Poetics by more than two centuries . Furthermore, I shall show that some of the words in the definition are a gloss added by Porphyry for the purposes of his own polemic. (shrink)