/ Dictionary / Index S sq. mm: Meaning and Definition of Find definitions for: sq. mm Pronunciation: [key] square millimeter; square millimeters. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. sq. mi. sqq. Related Content Daily Word Quiz: paradox Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language