We found 19 dictionaries that define the word april fools' day:

General (16 matching dictionaries)

1. April Fool's Day, April Fools' Day: Merriam-Webster
2. April Fool's Day, April Fools' Day: Oxford Learner's Dictionaries
3. April Fools' Day: American Heritage Dictionary of the English Language
4. April Fools' Day, April Fools' Day: Collins English Dictionary
5. April Fools' day: Vocabulary.com
6. April Fool's Day: Cambridge Advanced Learner's Dictionary
7. April Fool's Day, April Fools' Day: Wiktionary
8. April Fools' Day: The Wordsmyth English Dictionary-Thesaurus
9. april fools' day, april fools day: Dictionary.com
10. APRIL FOOLS DAY, April Fool's Day, April Fool's Day (disambiguation), April Fool's Day (novel), April Fools' Day, April Fools' Day (disambiguation), April Fools' Day (film), April Fool's day, April Fools' day, April Fools day, April fool's day, April fools' day, April fools day: Wikipedia, the Free Encyclopedia
11. April fools' day: Rhymezone
12. april fools day: FreeDictionary.org
13. april fools' day: Mnemonic Dictionary
14. April Fool's Day, April Fools' Day, April Fools Day: TheFreeDictionary.com
15. April Fools Day: Wikipedia, the Free Encyclopedia
16. april fools day: Longman Dictionary of Contemporary English

Computing (1 matching dictionary)

17. April-Fools' Day, April Fool's Day, April Fools' Day, April Fools Day: Encyclopedia

Miscellaneous (1 matching dictionary)

18. April Fool's Day: Holidays Around the World

Slang (1 matching dictionary)

19. April Fool's Day, April Fools' Day, april fools day: Urban Dictionary

Definitions from Wiktionary (April Fools' Day) ▸ noun:  The first day in April, when tricks and practical jokes are traditionally played Phrases: like april fools day, more... ▸ Words similar to april fools' day ▸ Usage examples for april fools' day ▸ Idioms related to april fools' day ▸ Wikipedia articles (New!) ▸ Words that often appear near april fools' day ▸ Rhymes of april fools' day ▸ Invented words related to april fools' day