add-on
[ad-on, -awn]
noun
a device or unit added to equipment or a construction: an add-on to a computer; a nice add-on to an old house.
an extra charge: Add-ons for taxes and tour guide fees boosted the price of the vacation to $2,500.
an additional item, as a rider or provision: This is just another legislative add-on.
anything added on: a hi-fi system that can be augmented with add-ons like extra speakers.
adjective
being installed or provided as an add-on: an add-on speaker system.
Origin of add-on
First recorded in 1945–50; noun and adj. use of verb phrase add on
Dictionary.com Unabridged
Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
Examples from the Web for add-on
Contemporary Examples of add-on
I once showed up to read and had been warned that a debut writer was also reading that night—a last minute add-on.
Unlike a phone, wearable technology is an add-on, an accessory, something that comes on top.
As a result, it felt like an add-on, meant to artificially moisten another otherwise dry address.
add-on
noun
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
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Online Etymology Dictionary, © 2010 Douglas Harper