Likely from ù- (“nominalizing prefix”) + pọ́n (“to be red, ripe”) + ẹrun (“mouth”). Cognates with Ìkálẹ̀ Yoruba ùpánrun, Itsekiri ùkpárun, Oǹdó Yoruba ùpánún, archaic Èkìtì Yoruba ụpọ́nrụn. Compare Ọ̀wọ̀ Yoruba ùpẹ̀nmẹ̀nrun, Ifè bèbèlè-arũ, Olukumi ekpùpẹrún, and Ede Nago ɛkpɔn. See Standard Yorùbá entry ètè for other terms used in the Yoruboid linguistic continuum.