There are different groups and societies in bamana culture. What we call a club is a tɔn. What we call a secret society is a jo. But how to write this word? Jo or jɔ? Thanks for helping me in that matter.
I ni ce, Kathan!
I believe that the form you are looking for is jo. The underlying tone of the word is low, so you may also see it written jò or jǒ depending on the author.
Jo however doesn’t only refer to a specific secret society. In fact, in many areas (including where I lived in Burkina Faso), it is the word that is commonly used for a “fetish” or “power object”. By extension, it may also refer to groups of people that are linked or allied via a fetish. I think that this is where the idea of meaning “secret society” comes from 
(This broader meaning of jo is listed in the Bamadaba entry for the word too.)
Thank you coleman! I’m working on a bigger article about this topics and want to be clear in my writings. Best regards from Herman Kathan
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