We found 32 dictionaries that define the word this:

General (25 matching dictionaries)

1. this: Longman Dictionary of Contemporary English
2. this: Merriam-Webster
3. this: Oxford Learner's Dictionaries
4. this: American Heritage Dictionary of the English Language
5. this: Collins English Dictionary
6. this: Vocabulary.com
7. THis, This, This, This, This, This, This, This, This, This, this, this, this, this, this, this, this, this: Wordnik
8. this: Cambridge Advanced Learner's Dictionary
9. this: Wiktionary
10. this: Webster's New World College Dictionary, 4th Ed.
11. this: The Wordsmyth English Dictionary-Thesaurus
12. this: Infoplease Dictionary
13. this: Dictionary.com
14. this: Online Etymology Dictionary
15. this: Cambridge Essential American English Dictionary
16. THIS, This (Darius Rucker song), This (Is What I Wanted to Tell You), This (Java), This (Peter Hammill album), This (The X-Files), This (computer programming), This (computer science), This (fly), This: Wikipedia, the Free Encyclopedia
17. This: Online Plain Text English Dictionary
18. this: Webster's Revised Unabridged, 1913 Edition
19. this: AllWords.com Multi-Lingual Dictionary
20. this: Webster's 1828 Dictionary
21. this: FreeDictionary.org
22. this: TheFreeDictionary.com
23. This: Wordnik

Computing (2 matching dictionaries)

24. BABEL: Computer Oriented Abbreviations and Acronyms (No longer online)
25. This (Egypt): Encyclopedia

Medicine (1 matching dictionary)

26. online medical dictionary (No longer online)

Miscellaneous (4 matching dictionaries)

27. Navajo Code Talkers' Dictionary (No longer online)
28. THIS: Acronym Finder
29. AbbreviationZ (No longer online)
30. this: Idioms

(Note: See these as well.)

Definitions from Wiktionary ( ) ▸ adverb:  To the degree or extent indicated. ▸ noun:  (philosophy) Something being indicated that is here; one of these. Similar: another, particular, whole, that, Every, next, here, last, thing, entire, more... Opposite: that, those, other, different, elsewhere Phrases: at this, this time, with this, this way, like this, more... Adjectives: try, how, read, all, consider, what, hear, remember, preface, keep, check ▸ Word origin ▸ Words similar to this ▸ Usage examples for this ▸ Idioms related to this ▸ Wikipedia articles (New!) ▸ Popular adjectives describing this ▸ Words that often appear near this ▸ Rhymes of this ▸ Invented words related to this