[ pluhg-in ]
See synonyms for plug-in on
  1. 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.

  1. a plug-in appliance.

  2. 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.

Origin of plug-in

First recorded in 1920–25; adjective and noun use of verb phrase plug in Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use plug-in in a sentence

  • He surveyed a big switchboard and picked out an outlet marked "Pons Varolis for the plug-in."

    The Brain | Alexander Blade
  • Loose plug-in connections and hose-ends dangled about his lean body.

    Death of a Spaceman | Walter M. Miller
  • He climbed into the snapper-boat and hunted for the plug-in terminal.

    Rip Foster in Ride the Gray Planet | Harold Leland Goodwin
  • I was a replaceable plug-in unit, not an individual in my own right.

    Anchorite | Randall Garrett

British Dictionary definitions for plug in

plug in

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

  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

  1. 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′ ]

  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.

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