subtractionPronunciation: /səbˈtrakʃn/Translate subtraction | into French | into German | into Italian | into Spanish Definition of subtraction noun [mass noun] the process or skill of taking one number or amount away from another:subtraction of this figure from the total Mathematics the process of taking a matrix, vector, or other quantity away from another under specific rules to obtain the difference. subtraction in other Oxford dictionaries Definition of subtraction in the US English dictionary