We found 20 dictionaries that define the word knock on:

General (15 matching dictionaries)

1. knock on: Longman Dictionary of Contemporary English
2. knock-on, knock on: Merriam-Webster
3. knock-on: Oxford Learner's Dictionaries
4. knock-on, knock-on: Collins English Dictionary
5. knock on: Vocabulary.com
6. Knock-on, knock-on: Wordnik
7. knock-on, knock on: Wiktionary
8. Knock-on, Knock-on (rugby league), Knock-on (rugby union), Knock on: Wikipedia, the Free Encyclopedia
9. knock on: Rhymezone
10. knock on: FreeDictionary.org
11. knock on: Mnemonic Dictionary
12. knock-on, knock on: TheFreeDictionary.com
13. knock on: Dictionary.com

Computing (1 matching dictionary)

14. knock-on: Encyclopedia

Miscellaneous (1 matching dictionary)

15. knock on: Idioms

Sports (2 matching dictionaries)

16. Hickok Sports Glossaries (No longer online)
17. Knock-on: Sports Definitions

Tech (1 matching dictionary)

18. AUTOMOTIVE TERMS (No longer online)

(Note: See knock_ons as well.)

Definitions from Wiktionary (knock on) ▸ verb:  (ambitransitive, rugby) To commit a foul by knocking the ball forward. ▸ verb:  (slang) To have an affair; to commit adultery. Similar: knock, knock about, foul, knock back, pick up, push off, knock over, ship, knock down, tackle, more... Opposite: knock off, knock down, knock over, tap, pat Phrases: knock on wood, knock on effect, knock on the head, knock on effects, knock something on the head, more... Adjectives: knockdown, net, check, fair, run-on, rimless, slice, d, number one, alley oop, fallaway ▸ Words similar to knock on ▸ Usage examples for knock on ▸ Idioms related to knock on ▸ Wikipedia articles (New!) ▸ Words that often appear near knock on ▸ Rhymes of knock on ▸ Invented words related to knock on