Single number following IXOIX? (3)
I believe the answer is:
one
'single' is the definition.
('one' can be a synonym of 'single')
'number following ixoix?' is the wordplay.
'number' becomes 'e' (e is a kind of number).
'following' is a charade indicator (letters next to each other).
'ixoix?' becomes 'on' (I can't explain this - if you can you should give a lot more credence to this answer).
'e' put after 'on' is 'ONE'.
Can you help me to learn more?
(Other definitions for one that I've seen before include "Lowest cardinal number" , "Single person or thing" , "Half of two" , "Hour after midnight" , "doesn't count for much" .)