For example, B to C, E to F, or the inverse of X and I (8)
I believe the answer is:
semitone
'for example' is the definition.
The definition and answer can be both related to communication as well as being singular nouns.
Maybe you can see an association between them that I can't see?
'b to c e to f or the inverse of x and i' is the wordplay.
I cannot quite understand how this works, but
'to' is within the answer.
'e' is present in the answer.
'and' could be 'n' (common abbreviation for 'and') and 'n' is found in the answer.
'i' is within the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for semitone that I've seen before include "Small interval between notes" , "Interval between adjacent keys, on a piano say" , "100 cents" , "One twelfth of an octave" , "Short musical interval" .)