fourth dimension


: a dimension in addition to length, breadth, and depth
specifically : a coordinate in addition to three rectangular coordinates especially when interpreted as the time coordinate in a space-time continuum
: something outside the range of ordinary experience
fourth-dimensional adjective

Example Sentences

Recent Examples on the Web Albert Einstein believed space and time made up a fourth dimension. Tim Newcomb, Popular Mechanics, 30 Jan. 2023 An example from a string theorist gives a view of what a fourth dimension could be. Tim Newcomb, Popular Mechanics, 30 Jan. 2023 There’s no need to assume that the fourth dimension must already exist out into infinity. Zeeya Merali, Discover Magazine, 29 Apr. 2015 The Time Machine, actor Rod Taylor plays a Victorian-era inventor who journeys into the fourth dimension on a sled attached to a large clock. Bill Andrews, Discover Magazine, 31 May 2018 Thus, Ellis’ model of time retains enough of the block universe to match with relativity’s predictions, but without needing to take Einstein’s drastic last step of assuming that the fourth dimension is solidified into the infinite future. Zeeya Merali, Discover Magazine, 29 Apr. 2015 That fourth dimension of human interaction and imprint is something Fendi rightly observes is in rich supply in Miami. Luke Leitch, Vogue, 29 Nov. 2022 In the same way, a fourth dimension gives a knot a lot more leeway — too much, in fact. Quanta Magazine, 18 May 2022 The innovation also adds a fourth dimension: emotional insight. Tara Mcnamara, Variety, 3 Mar. 2022 See More

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'fourth dimension.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

Word History

First Known Use

1875, in the meaning defined at sense 1

Time Traveler
The first known use of fourth dimension was in 1875

Dictionary Entries Near fourth dimension

Cite this Entry

“Fourth dimension.” Dictionary, Merriam-Webster, Accessed 26 Mar. 2023.

Last Updated: - Updated example sentences
Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!

A Good Old-Fashioned Quiz

How Strong Is Your Vocabulary?

Test your vocabulary with our 10-question quiz!

Solve today's spelling word game by finding as many words as you can with using just 7 letters. Longer words score more points.

Can you make 12 words with 7 letters?