/ Dictionary / Index R round lot: Meaning and Definition of Find definitions for: round' lot' Pronunciation: [key] — Stock Exchange. Stock Exchange. the conventional unit or quantity in which commodities or securities are bought and sold. (in a transaction) a quantity of 100 shares of a stock that is active or 10 shares of a stock that is inactive. Cf. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. roundlet round-lotter Related Content Daily Word Quiz: censure Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language