The meaning of Oṣé is very simple. Oṣe is also written as Oshey by non fluent Yoruba Enthusiasts. Oshey is the way Oṣé sounds when pronounced.
Oṣé/Oshey means Thank you. It could also be used to hail someone for their remarkable performance in something. Usually, Oṣé/Oshey is used to hail another person in Yoruba land. But the literal meaning of Oṣé/Oshey in Yorùbá is Thank you/Thanks. When Yoruba People want to use Oṣé/Oshey to hail, they shout it like “Oshey!!!!”. It is a common word among Yoruba word and Slang among Yoruba youths especially.
Oṣé is a Yoruba way of saying Thank You.