We found 22 dictionaries that define the word on the side:

General (14 matching dictionaries)

1. on the side: Longman Dictionary of Contemporary English
2. on the side: Merriam-Webster
3. on the side: Oxford Learner's Dictionaries
4. on the side: Collins English Dictionary
5. on the side: Vocabulary.com
6. on the side: Cambridge Advanced Learner's Dictionary
7. on the side: Wiktionary
8. on the side: Dictionary.com
9. on the side: Rhymezone
10. on the side: FreeDictionary.org
11. on the side: Mnemonic Dictionary
12. on the side: TheFreeDictionary.com

Business (1 matching dictionary)

13. on the side: Legal dictionary

Computing (1 matching dictionary)

14. on the side: Encyclopedia

Medicine (2 matching dictionaries)

15. on the side: Merriam-Webster Medical Dictionary
16. on the side: Medical dictionary

Miscellaneous (1 matching dictionary)

17. on the side: Idioms

Slang (2 matching dictionaries)

18. American-Australian Slang Dictionary (No longer online)
19. on the side: Urban Dictionary

Tech (1 matching dictionary)

20. AUTOMOTIVE TERMS (No longer online)

Definitions from WordNet (on the side) ▸ adverb:  without official authorization ("He had made some money on the side") Opposite: centered, in middle, aligned, symmetrical, balanced Phrases: get out of bed on the wrong side, get up on the wrong side of the bed, look on the bright side, got up on the wrong side of the bed, looked on the black side, more... ▸ Words similar to on the side ▸ Usage examples for on the side ▸ Idioms related to on the side ▸ Wikipedia articles (New!) ▸ Words that often appear near on the side ▸ Rhymes of on the side ▸ Invented words related to on the side