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.

Origin of plug-in

First recorded in 1920–25; adj., noun use of verb phrase plug in Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for plug-in

Contemporary Examples of plug-in

Historical Examples of plug-in

  • He climbed into the snapper-boat and hunted for the plug-in terminal.

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

    The Brain

    Alexander Blade

Word Origin and History for plug-in

1922, from plug (v.) + in (adv.).

Online Etymology Dictionary, © 2010 Douglas Harper

plug-in in Science



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.