I don't know how to interpret (Sierra Leone) names . .
in the entry . . . S/ Leoneon, what does the S/ mean? Usually it means 'signed by'. ???
Signed by is usually indicated by /S/ - with the S between 2 slashes. Known as a conformed signature.
In this case - without seeing the record - I suspect the S is for Sierra, to save having to write the full place name.
You have to be careful when working on the Sierra Leone project. If you are working on a birth register, some times the village, chiefdom, or ethnicity, may be included in the space with the names. The name usually comes first.
As Áine Ni Donnghaile said you are probably looking at their ethnicity. S/Leoneon not part of the name.
hope this helps