From Wiktionary, the free dictionary
Possibly from Proto-Yoruboid *ó-cù , cognate with Igala óchù, possibly equivalent to o- (“nominalizing prefix”) + ṣù (“to be round”)
oṣù
- moon; (in particular) new moon
- Synonym: òṣùpá
- (by extension) month
- (Kojoda months) oṣù Kọ́jọ́dá; Òkúdu (“June”), Agẹmọ (“July”), Ògún (“August”), Òwéwe (“September”), Ọ̀wàrà (“October”), Bélú (“November”), Ọ̀pẹ̀ (“December”), Ṣẹ̀rẹ́ (“January”), Èrèlé (“February”), Ẹ̀rẹ̀nà (“March”), Igbe (“April”), Ẹ̀bìbì (“May”) (Category: yo:Kojoda months)