Now accepted and proved by the relativity theory to be time
An extension at right-angles to the three familiar directions of up-down, forward-backward, and side-to-side. In physics, especially in relativity theory, time is often regarded as the fourth dimension of the spacetime continuum in which we live. But what meaning can be attached to a fourth spatial ...
[n] - the fourth coordinate that is required (along with three spatial dimensions) to specify a physical event
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 ...