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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.

Marjorie Radlo-Zandi, an angel investor in Boston, found that her Audi Q5 plug-in hybrid was the perfect blend of EV and gasoline vehicle.

From The Wall Street Journal • Apr. 10, 2026

Power indicates that as of summer 2025, plug-in hybrid vehicles had more problems in their first 90 days than conventional vehicles and fully electric ones.

From The Wall Street Journal • Apr. 10, 2026

Searches for used plug-in hybrids rose 7%, while searches for used traditional hybrids rose 4%.

From Barron's • Apr. 7, 2026

The government said it was working with major retailers like Lidl and Amazon to make plug-in solar available on the high street.

From BBC • Mar. 23, 2026

The other food—sliced turkey, ham, roast beef, and salami, a big tub of tuna salad, and meatballs in a plug-in pot—was off-limits.

From "When You Reach Me" by Rebecca Stead

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.