The paper firstly focuses on a rare vox, that is, the verb \u3bc\u3b5\u3c4\u3af\u3c3\u3c7\u3c9 (\u2018to participate\u2019). This has been found in two unexplored sources: the \u3a0 text of Lambda 1075b19 and the Ai Khanoum so called \u2018papyrus\u2019 in II.9, 11, IV.8-9. Using the verb \u3bc\u3b5\u3c4\u3af\u3c3\u3c7\u3c9 with reference to the theory of ideas testifies for a subsequent phase to Plato\u2019s middle dialogues in defining the theory and the related lexicon. (see Plato\u2019s Parmenides 128e-130c). The phase was intermediate and probably transitory. Xenocrates is likely to have played a role, as Margherita Isnardi Parente hypothesizes. This allows for deeper connection between the Aristotelian theories and Plato's Academy
