›the amount or degree of difference between a higher amount and a lower amount: He was reelected by a wide margin.›A margin for error is the amount by which you can make a mistake without risking complete failure: There is no margin for error – it’s got to work the first time.›A margin of error is the degree to which a calculation can be wrong without changing how accurate the final result is: The poll had a margin of error of plus or minus 4%.