Gas from egg Seth considered funny (8)
I believe the answer is:
nitrogen
'gas' is the definition.
(I know that nitrogen is a type of gas)
'egg seth considered funny' is the wordplay.
I cannot quite understand how this works, but
'egg' could be 'nit' (a nit is an insect egg) and 'nit' is located in the answer.
The remaining letters 'rogen' is a valid word which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
'from' is the link.
Can you help me to learn more?
(Other definitions for nitrogen that I've seen before include "chemists have fixation with?" , "Chemical element" , "It forms about four-fifths of atmosphere" , "Common gas, N" , "Atomic number 7" .)