SUMMATION Meaning of SUMMATION in English [ sʌ'meɪʃ(ə)n ]■ noun1》 the process of adding things together. ↘a sum total. 2》 the action of summing up. ↘a summary.Derivatives~al adjectivesummative adjective Concise Oxford English vocab. Сжатый оксфордский словарь английского языка. 2004