We found 23 dictionaries that define the word fourth dimension:

General (18 matching dictionaries)

1. fourth dimension: Merriam-Webster
2. fourth dimension: Oxford Learner's Dictionaries
3. fourth dimension: American Heritage Dictionary of the English Language
4. fourth dimension: Collins English Dictionary
5. fourth dimension: Vocabulary.com
6. the fourth dimension: Cambridge Advanced Learner's Dictionary
7. fourth dimension: Wiktionary
8. fourth dimension: The Wordsmyth English Dictionary-Thesaurus
9. fourth dimension: Infoplease Dictionary
10. fourth dimension: Dictionary.com
11. Fourth Dimension (Radiophonic album), Fourth Dimension (Stratovarius album), Fourth Dimension, Fourth dimension (disambiguation), Fourth dimension, The Fourth Dimension (Hypocrisy album), The Fourth Dimension (Jack McDuff album), The Fourth Dimension (book), The Fourth Dimension (company), The Fourth Dimension (film), The Fourth Dimension: Wikipedia, the Free Encyclopedia
12. fourth dimension: Rhymezone
13. fourth dimension: FreeDictionary.org
14. fourth dimension: Mnemonic Dictionary
15. fourth dimension: TheFreeDictionary.com
16. fourth dimension: Longman Dictionary of Contemporary English

Art (1 matching dictionary)

17. fourth dimension: ArtLex Lexicon of Visual Art Terminology

Business (2 matching dictionaries)

18. Construction Term Glossary (No longer online)
19. BusinessDictionary.com (No longer online)

Computing (1 matching dictionary)

20. fourth dimension: Encyclopedia

Slang (1 matching dictionary)

21. fourth dimension: Urban Dictionary

(Note: See fourth-dimensional as well.)

Definitions from Wiktionary (fourth dimension) ▸ noun:  (algebraic geometry) The fourth coordinate indicating a position along the fourth axis. ▸ noun:  (physics) The dimension of time. Similar: time, coordinate axis, x-direction, z-axis, co-ordinate axis, space, z-direction, applicant, y-direction, quadrant, more... Opposite: three-dimensional, spatial, Euclidean Types: time, more... Phrases: Fourth dimension in art, Fourth dimension in literature, more... Adjectives: right, tangent, reflex, angular, vertical, diagonal, perpendicular, complementary, multipoint, oblique, concyclic ▸ Words similar to fourth dimension ▸ Usage examples for fourth dimension ▸ Idioms related to fourth dimension ▸ Wikipedia articles (New!) ▸ Words that often appear near fourth dimension ▸ Rhymes of fourth dimension ▸ Invented words related to fourth dimension