/ Dictionary / Index P plug-in: Meaning and Definition of Find definitions for: plug-in Pronunciation: (plug'in"), [key] — adj. 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. —n. plug (def. 3). jack (def. 3). a plug-in appliance. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: plug-in (Thesaurus) plug hat plugola Related Content Daily Word Quiz: penchant Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language