Likely from Yoruba ọ̀sẹ̀, compare include Ìkálẹ̀ Yoruba ọ̀hẹ̀, Ìjẹ̀bú Yoruba ọ̀sẹ̀n
osɛ̀ (plural osɛ̀ lɛ́) (Benin)