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Synonyms

plug-in

American  
[pluhg-in] / ˈplʌgˌɪn /

adjective

  1. capable of or designed for being connected to an electrical power source by plugging in or inserting: a plug-in transistor.

    a plug-in hair dryer;

    a plug-in transistor.

noun

  1. plug.

  2. jack.

  3. a plug-in appliance.

  4. Computers. a small software program that builds additional functionality into a stand-alone computer application.

    Your web browser can’t display this video without a plug-in.
plug in British  

verb

  1. (tr, adverb) to connect (an electrical appliance) with a power source by means of an electrical plug

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

noun

  1. a device that can be connected by means of a plug

  2. computing a module or piece of software that can be added to a system to provide extra functions or features, esp software that enhances the capabilities of a web browser

  3. computing ( as modifier )

    plug-in memory cards
"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
plug-in Scientific  
/ plŭg′ĭn′ /

  1. An accessory software or hardware package that is used in conjunction with an existing application or device to extend its capabilities or provide additional functions.

Etymology

Origin of plug-in

First recorded in 1920–25; adjective and noun use of verb phrase plug in

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

Half of surveyed car shoppers said they are considering an EV or a plug-in hybrid EV due to rising gas prices.

From MarketWatch • Apr. 25, 2026

Porsche last year said it would scale back its EV ambitions following the slow uptake of the technology and instead expand its lineup with more gas-powered and plug-in hybrid models.

From The Wall Street Journal • Apr. 10, 2026

It also said plug-in panels that homeowners can self-install on balconies would be available in supermarkets in the coming months.

From BBC • Mar. 23, 2026

The Chinese plug-in hybrid specialist is grappling with flagging sales while it tries to make headway in the highly competitive full-electric market.

From The Wall Street Journal • Mar. 16, 2026

I dug up Radar’s e-mail about his Omnictionary program and downloaded the plug-in.

From "Paper Towns" by John Green

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.