We found 13 dictionaries that define the word summations:

General (8 matching dictionaries)

1. summations: Merriam-Webster
2. summations: Collins English Dictionary
3. summations: Vocabulary.com
4. Summations, summations: Wordnik
5. summations: Cambridge Advanced Learner's Dictionary
6. summations: Wiktionary
7. summations: Dictionary.com
8. summations: TheFreeDictionary.com

Business (2 matching dictionaries)

9. summations: Merriam-Webster Legal Dictionary
10. summations: Legal dictionary

Computing (1 matching dictionary)

11. summations: Encyclopedia

Medicine (2 matching dictionaries)

12. summations: Merriam-Webster Medical Dictionary
13. summations: Medical dictionary

(Note: See summation as well.)

Definitions from Wiktionary (summation) ▸ noun:  summarization; summary; summing up. ▸ noun:  (mathematics) summing; summing up; adding (adding up) of a series of items. ▸ Also see summation Opposite: subtractions, deductions, reductions ▸ Words similar to summations ▸ Usage examples for summations ▸ Idioms related to summations ▸ Wikipedia articles (New!) ▸ Popular adjectives describing summations ▸ Words that often appear near summations ▸ Rhymes of summations ▸ Invented words related to summations