/ Dictionary / Index L least squares: Meaning and Definition of Find definitions for: least' squares' Pronunciation: [key] — Statistics. Statistics. a method of estimating values from a set of observations by minimizing the sum of the squares of the differences between the observations and the values to be found. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. least significant digit least upper bound Related Content Daily Word Quiz: arboreal Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language