The word "metaphysics" appears to have been coined by the first century AD editor who assembled various small selections of Aristotle's works to the treatise we know by the name Metaphysics.
ðə wˈɜːd "mˌɛɾəfˈɪzɪks" ɐpˈɪɹz tə hɐvbɪn kˈɔɪnd baɪ ðə fˈɜːst sˈɛntʃɚɹi ˌeɪdˈiː ˈɛdɪɾɚ hˌuː ɐsˈɛmbəld vˈɛɹiəs smˈɔːl sᵻlˈɛkʃənz ʌv ˈæɹɪstˌɑːɾəlz wˈɜːks tə ðə tɹˈiːɾɪz wiː nˈoʊ baɪ ðə nˈeɪm mˌɛɾəfˈɪzɪks.