We found 20 dictionaries that define the word upper case:

General (15 matching dictionaries)

1. upper case: Longman Dictionary of Contemporary English
2. upper case: Merriam-Webster
3. upper case: Oxford Learner's Dictionaries
4. upper-case, upper-case, upper case: Collins English Dictionary
5. upper-case, upper case: Wordnik
6. upper case: Cambridge Advanced Learner's Dictionary
7. upper-case, upper case: Wiktionary
8. upper-case, upper case: The Wordsmyth English Dictionary-Thesaurus
9. upper case: Dictionary.com
10. Upper CASE, Upper-case, Upper case: Wikipedia, the Free Encyclopedia
11. upper case: Rhymezone
12. upper case: FreeDictionary.org
13. upper-case, upper case: TheFreeDictionary.com

Art (1 matching dictionary)

14. Upper Case: Glossary of English Grammar Terms

Computing (2 matching dictionaries)

15. upper case: CCI Computer
16. Upper-case, upper CASE: Encyclopedia

Science (1 matching dictionary)

17. upper case: LITTLE EXPLORERS(TM) Picture Dictionary

Tech (1 matching dictionary)

18. Sweetwater Music (No longer online)

(Note: See upper_cases as well.)

Definitions from Wiktionary (upper case) ▸ noun:  The capital letters A, B, C, ... as opposed to the small letters a, b, c, .... Similar: capital, upper-case letter, uppercase, capital letter, lower case, majuscule, lowercase, caps, block capital, capitalisation, more... Types: A, B, C, D, E, F, G, H, I, J, more... Phrases: upper case letter, more... Adjectives: case, lowercased, case-sensitive, case insensitive, inferior, minuscule, uppercase, superior, capital, boldface, adscript ▸ Words similar to upper case ▸ Usage examples for upper case ▸ Idioms related to upper case ▸ Wikipedia articles (New!) ▸ Words that often appear near upper case ▸ Rhymes of upper case ▸ Invented words related to upper case