In that particular change he introduces the concept of potentiality (dynamis) and actuality (entelecheia) in association with the matter and the form.
ɪn ðæt pɚtˈɪkjʊlɚ tʃˈeɪndʒ hiː ˌɪntɹədˈuːsᵻz ðə kˈɑːnsɛpt ʌv pətˈɛnʃɪˈælᵻɾi dˈaɪnæmiz ænd ˌæktʃuːˈælᵻɾi ɛntˈɛlɪtʃˌeɪə ɪn ɐsˌoʊsɪˈeɪʃən wɪððə mˈæɾɚ ænd ðə fˈɔːɹm.