add-on
1 of 2noun
ˈad-ˌän 
-ˌȯn
: something added on: such as
a
: a sum or amount added on
b
: something (such as an accessory or added feature) that enhances the thing it is added to
computer hardware add-ons
add-on
2 of 2adjective
1
: being or able to be added on
an add-on device
2
: able to be added to
add-on certificates of deposit
Synonyms
Noun
- accessory
- accessary
- accoutrement
- accouterment
- adapter
- adaptor
- adjunct
- appendage
- appliance
- attachment
- option
See all Synonyms & Antonyms 
Word History
First Known Use
Noun
1930, in the meaning defined above
Adjective
1955, in the meaning defined at sense 1
Legal Definition
add-on
adjective
1
: being or able to be added on
add-on no-fault benefits
2
: able to be added to
add-on certificates of deposit
add-on
noun
as in option
something that is not necessary in itself but adds to the convenience or performance of the main piece of equipment a blow-dryer that comes with a couple of add-ons for people who are serious about styling their hair Synonyms & Similar Words
Relevance
- option
- accessory
- appliance
- adapter
- adjunct
- enhancement
- additive
- adaptor
- attachment
- appendage
- accessary
- equipment
- supplement
- complement
- accompaniment
- accouterment
- accoutrement
- auxiliary
- filler
- subsidiary
- extra
- ornament
- incidental
- adornment
- decoration
- luxury
- furnishings
- trappings
- embellishment
- embroidery
- nonessential
- amenity
- trimming
- doodad
- frill
- trim
- appurtenances
- garnish
- paraphernalia
- habiliment(s)
- nonnecessity
- bells and whistles
Antonyms & Near Antonyms
- essential
- requirement
- necessity
- requisite