[ pluhg-in ]
/ ˈplʌgˌɪn /
Save This Word!

capable of or designed for being connected to an electrical power source by plugging in or inserting: a plug-in hair dryer;a plug-in transistor.
a plug-in appliance.
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.
"Is" it time for a new quiz? "Are" you ready? Then prove your excellent skills on using "is" vs. "are."
Question 1 of 7
IS and ARE are both forms of which verb?

Origin of plug-in

First recorded in 1920–25; adjective and noun use of verb phrase plug in
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2022

British Dictionary definitions for plug-in

plug in

(tr, adverb) to connect (an electrical appliance) with a power source by means of an electrical plug
noun plug-in
a device that can be connected by means of a plug
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
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

Scientific definitions for plug-in

[ plŭgĭn′ ]

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.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.