add-on

American  

[ad-on, -awn] / ˈædˌɒn, -ˌɔn /

noun

1. a device or unit added to equipment or a construction.

   an add-on to a computer;

   a nice add-on to an old house.

2. an extra charge.

   Add-ons for taxes and tour guide fees boosted the price of the vacation to $2,500.

3. an additional item, as a rider or provision.

   This is just another legislative add-on.

4. anything added on.

   Our sable faux fur vest is an easy add-on for dressy or casual occasions.

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adjective

1. being installed or provided as an add-on.

   Add-on packs for this game are just a few dollars.

add-on British  

noun

1. a feature that can be added to a standard model or package to give increased benefits

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Etymology

Origin of add-on

First recorded in 1945–50; noun and adj. use of verb phrase add on

Example Sentences

If they had bought an add-on then that cost would have been covered.

From BBC • May 10, 2026

Chief Executive Todd Penegor said the pizza chain is aiming to address the issue by improving its value perception and stepping up innovation to attract new customers, sell more premium pizzas and boost add-on purchases.

From The Wall Street Journal • May 7, 2026

Spirit grew quickly in the early 2000s, paving the way for other budget carriers such as Frontier to offer low-cost tickets with countless paid add-on options for seats and in-flight beverages.

From Los Angeles Times • May 1, 2026

Any gains airlines have seen in recent years are at least partly tied to the fact they’ve been able to build a solid revenue stream from all those add-on fees, experts say.

From MarketWatch • Apr. 10, 2026

When Margaret came back to the add-on living room, she poured us each a glass of cold cider, and we sat at the kitchen table and talked.

From "Silent To The Bone" by E.L. Konigsburg

Related Words

• preservative
• supplement