We found 34 dictionaries that define the word summation:

General (24 matching dictionaries)

1. summation: Longman Dictionary of Contemporary English
2. summation: Merriam-Webster
3. summation: Oxford Learner's Dictionaries
4. summation: American Heritage Dictionary of the English Language
5. summation: Collins English Dictionary
6. summation: Vocabulary.com
7. Summation, summation: Wordnik
8. summation: Cambridge Advanced Learner's Dictionary
9. summation: Wiktionary
10. summation: Webster's New World College Dictionary, 4th Ed.
11. summation: The Wordsmyth English Dictionary-Thesaurus
12. summation: Infoplease Dictionary
13. summation: Dictionary.com
14. summation: Online Etymology Dictionary
15. Summation (disambiguation), Summation (neurophysiology), Summation: Wikipedia, the Free Encyclopedia
16. Summation: Online Plain Text English Dictionary
17. summation: Webster's Revised Unabridged, 1913 Edition
18. summation: Rhymezone
19. Summation: AllWords.com Multi-Lingual Dictionary
20. summation: FreeDictionary.org
21. summation: Mnemonic Dictionary
22. summation: TheFreeDictionary.com

Business (4 matching dictionaries)

23. summation: Merriam-Webster Legal Dictionary
24. summation: Law.com Dictionary
25. Everybody's Legal Dictionary (No longer online)
26. summation: Legal dictionary

Computing (1 matching dictionary)

27. summation: Encyclopedia

Medicine (4 matching dictionaries)

28. summation: Merriam-Webster Medical Dictionary
29. Summation: MedFriendly Glossary
30. online medical dictionary (No longer online)
31. summation: Medical dictionary

Science (1 matching dictionary)

32. summation: PlanetMath Encyclopedia

(Note: See summational as well.)

Definitions from Wiktionary ( ) ▸ noun:  summarization; summary; summing up. ▸ noun:  (mathematics) summing; summing up; adding (adding up) of a series of items. Similar: summing up, addition, rundown, plus, sum-up, summing, summarization, summarisation, summing-up, wrap-up, more... Opposite: subtraction, difference, deduction Phrases: temporal summation, spatial summation, summation convention, summation notation, summation method, more... Adjectives: spatial, temporal, simple, final, horizontal, double, linear, brief, mere, second, direct Colors:     blue,     red,     green,     yellow,     orange, more... ▸ Word origin ▸ Words similar to summation ▸ Usage examples for summation ▸ Idioms related to summation ▸ Wikipedia articles (New!) ▸ Popular adjectives describing summation ▸ Words that often appear near summation ▸ Rhymes of summation ▸ Invented words related to summation