To cross out with lines or other markings. See Synonyms at erase. To annul or invalidate. To mark or perforate (a postage stamp or check, for example) to indicate that it may not be used again. To equalize or make up for; offset: Today's decline in stock price canceled out yesterday's gain. Mathematics To remove (a common factor) from the numerator and denominator of a fractional expression. Mathematics To remove (a common factor or term) from both sides of an equation or inequality. Printing To omit or delete. To neutralize one another; counterbalance: two opposing forces that canceled out. The act or an instance of canceling; a cancellation. Printing Deletion of typed or printed matter. Printing The matter deleted. Printing A replacement for deleted matter.