We found 28 dictionaries that define the word ageing:

General (20 matching dictionaries)

1. ageing: Merriam-Webster
2. ageing, ageing: Oxford Learner's Dictionaries
3. ageing: American Heritage Dictionary of the English Language
4. ageing: Collins English Dictionary
5. ageing: Vocabulary.com
6. Ageing, ageing: Wordnik
7. ageing: Cambridge Advanced Learner's Dictionary
8. ageing: Wiktionary
9. ageing: Infoplease Dictionary
10. ageing: Dictionary.com
11. ageing: Cambridge Essential American English Dictionary
12. Ageing (disambiguation), Ageing: Wikipedia, the Free Encyclopedia
13. ageing: Rhymezone
14. ageing: AllWords.com Multi-Lingual Dictionary
15. ageing: FreeDictionary.org
16. ageing: Mnemonic Dictionary
17. ageing: TheFreeDictionary.com
18. ageing: Longman Dictionary of Contemporary English

Business (2 matching dictionaries)

19. ageing: Legal dictionary
20. ageing: Financial dictionary

Computing (1 matching dictionary)

21. ageing: Encyclopedia

Medicine (2 matching dictionaries)

22. ageing: Merriam-Webster Medical Dictionary
23. ageing: Medical dictionary

Miscellaneous (1 matching dictionary)

24. ageing: Idioms

Tech (2 matching dictionaries)

25. AUTOMOTIVE TERMS (No longer online)
26. Wine Glossary (No longer online)

(Note: See age as well.)

Definitions from Wiktionary ( ) ▸ noun:  UK, Australia, New Zealand, and South Africa standard spelling of aging. ▸ adjective:  UK, Australia, New Zealand, and South Africa standard spelling of aging. Similar: mellowing, ripening, senescent, old, offence, Austral English, anglicization, Australian English, Aussie, grey fox, more... Opposite: rejuvenation, youthfulness, revitalization Types: biological, chronological, physical, social, emotional, intellectual, spiritual, more... Phrases: anti ageing, biology of ageing, Population ageing, Ageing of Europe, Evolution of ageing, more... Adjectives: normal, premature, successful, natural, human, rapid, accelerated, artificial, physical, demographic, healthy Colors:     gray,     silver,     white,     beige,     taupe, more... ▸ Words similar to ageing ▸ Usage examples for ageing ▸ Idioms related to ageing ▸ Wikipedia articles (New!) ▸ Popular adjectives describing ageing ▸ Popular nouns described by ageing ▸ Words that often appear near ageing ▸ Rhymes of ageing ▸ Invented words related to ageing