Hello,
I agree with Sahil that you cannot reference specfic terms created within an application but you have to create a new application for the same.
Alternatively i would suggest you to use application-sets and application combination. Using this combination you can create multiple applications and call them under an application-set and you can either use application-set or application specifically as well in the security policies as per the requirement.
You can create applications and call them in an application-set as per the below example:-
set applications application TCP53 protocol tcp
set applications application TCP53 destination-port 53
set applications application UDP53 protocol udp
set applications application UDP53 destination-port 53
set applications application-set DNS application TCP53
set applications application-set DNS application UDP53
Thanks,
Pulkit Bhandari
Please mark my response as Solution Accepted if it Helps, Kudos are Appreciated too.