- Physics, Mathematics. a dimension in addition to length, width, and depth, used so as to be able to employ geometrical language in discussing phenomena that depend on four variables: Time is considered a fourth dimension for locating points in space-time.
- something beyond the kind of normal human experience that can be explained scientifically: The story deals with ESP and other excursions into the fourth dimension.
Origin of fourth dimension
First recorded in 1870–75
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
- the dimension of time, which is necessary in addition to three spatial dimensions to specify fully the position and behaviour of a point or particle
- the concept in science fiction of a dimension in addition to three spatial dimensions, used to explain supernatural phenomena, events, etc
- Time regarded as a coordinate dimension. A fourth dimension is required by relativity theory, along with three spatial dimensions, to specify completely the location of any event.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.