/ Dictionary / Index M Merseyside: Meaning and Definition of Find definitions for: Mer•sey•side Pronunciation: (mûr'zē-sīd"), [key] — n. a metropolitan county in W England. 1,588,400; 250 sq. mi. (648 sq. km). Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. Mersey Mersin Related Content Daily Word Quiz: resilient Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language