/ Dictionary / Index M middle-aged: Meaning and Definition of Find definitions for: mid•dle-aged Pronunciation: (mid'l-ājd'), [key] — adj. being of the age intermediate between youth and old age, roughly between 45 and 65. characteristic of or suitable for persons of this age. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: middle-aged (Thesaurus) middle age Middle Ages Related Content Daily Word Quiz: vertigo Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language