Old vessel with nitrogen? Some other gas (5)
I believe the answer is:
argon
'other gas' is the definition.
'argon' can be an answer for 'gas' (argon is a gas). I'm not certain of the 'other' bit.
'old vessel with nitrogen? some' is the wordplay.
'old vessel' becomes 'argo' (I've seen this before).
'with' says to put letters next to each other.
'some' indicates taking the first letters.
The first letter of 'nitrogen' is 'n'.
'argo'+'n'='ARGON'
Can you help me to learn more?
(Other definitions for argon that I've seen before include "Noble gas, Ar" , "rare gas" , "Inert eighteen ac gas" , "Noble gas used in light bulbs" , "Inert gas, present in small amounts in the air" .)