Argon or neon, eg (5,3)
I believe the answer is:
inert gas
This clue could be a double definition.
'argon' is the first definition.
The answer and definition can be both substances as well as being singular nouns.
Maybe there's an association between them I don't understand?
'neon eg' is the second definition.
(I know that neon is a type of inert gas)
'or' is the link.
Can you help me to learn more?
(Other definitions for inert gas that I've seen before include "Eg, krypton or argon" , "He perhaps" , "He, amongst others" , "Passive element in the helium group" , "Eg, helium or argon" .)