noun 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.
Compare odd lot.
Origin of round lot
First recorded in 1900–05
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019