add-on
noun [ C ]
uk/ˈædɒn/ ussomething extra that is added to a product to make it better:
DVDs often include bonus endings and other add-ons.
an add-on to sth Many companies offer legal expenses cover as an add-on to home insurance policies.
add-on parts/products/services
IT
a piece of computer equipment or software that is added to a computer so that the computer can do more or different things:
an add-on to sth It would require an add-on to a browser to make it all work.
add-on devices/features/software
add-on
adjective [ only before noun ]
ukusextra:
add-on costs/fees/charges Car dealers profit from questionable add-on charges, such as for extended warranties.