We found 30 dictionaries that define the word autumnal:

General (23 matching dictionaries)

1. autumnal: Merriam-Webster
2. autumnal: Oxford Learner's Dictionaries
3. autumnal: Collins English Dictionary
4. autumnal: Vocabulary.com
5. Autumnal, autumnal: Wordnik
6. autumnal: Cambridge Advanced Learner's Dictionary
7. autumnal: Wiktionary
8. autumnal: The Wordsmyth English Dictionary-Thesaurus
9. autumnal: Infoplease Dictionary
10. Autumnal, autumnal: Dictionary.com
11. Autumnal: Wikipedia, the Free Encyclopedia
12. Autumnal: Online Plain Text English Dictionary
13. autumnal: Webster's Revised Unabridged, 1913 Edition
14. autumnal: Rhymezone
15. Autumnal: AllWords.com Multi-Lingual Dictionary
16. autumnal: Webster's 1828 Dictionary
17. autumnal: FreeDictionary.org
18. autumnal: Mnemonic Dictionary
19. autumnal: TheFreeDictionary.com
20. autumnal: Longman Dictionary of Contemporary English
21. autumnal: Merriam-Webster

Art (1 matching dictionary)

22. Epicurus.com Tea Glossary (No longer online)

Computing (1 matching dictionary)

23. autumnal: Encyclopedia

Medicine (1 matching dictionary)

24. online medical dictionary (No longer online)

Science (1 matching dictionary)

25. Botanical Terms (No longer online)

Slang (1 matching dictionary)

26. Autumnal: Urban Dictionary

Tech (2 matching dictionaries)

27. Glossary of Meteorology (No longer online)
28. Lake and Water Word Glossary (No longer online)

(Note: See autumn as well.)

Definitions from Wiktionary ( ) ▸ adjective:  Of or relating to autumn. ▸ adjective:  Past the middle of life; in the third stage. Similar: mature, aestivoautumnal, equinoctial, seasonal, Vernal, æquinoctial, aestive, summersome, midsummery, estival, more... Opposite: vernal, spring Types: fall, falling, fallen, falling leaves, fallen leaves, more... Phrases: autumnal equinox, autumnal equinoxes, autumnal point, autumnal signs, autumnal equinox day, more... Adjectives: aestivo, more, estivo, first, late, heavy, rich, yellow, good, early, french Colors:     amber,     maroon,     rust,     ochre,     sienna, more... ▸ Words similar to autumnal ▸ Usage examples for autumnal ▸ Idioms related to autumnal ▸ Wikipedia articles (New!) ▸ Popular nouns described by autumnal ▸ Words that often appear near autumnal ▸ Rhymes of autumnal ▸ Invented words related to autumnal