a union of space and time originally emerging from special relativity. Can be viewed as the "fabric" out of which the universe is fashioned; it constitutes the dynamical arena within which the events of the universe take place.

Our local, solid, 3-D living environment (also referred to as the spacetime continuum). The matter/energy building material of our local 3-D universe. A particle evaporation of n-space.

We are used to thinking of our world as having 3 space dimensions and 1 time dimension. From the theory of special relativity we know that space and time are intimately linked. Therefore we combine them into a 4-dimensional spacetime (or 3+1 dimensional spacetime to be precise). Then the trajectory of a moving particle in this spacetime is an invariant object called a 'worldline'. How we measure the space and time dimensions amounts to a preferred set of coordinate axes which depends on our frame of reference. We generalize to higher dimensional spacetimes simply by adding more space dimensions (e.g. 10-dimensional spacetime has 9 space dimensions and 1 time dimension).

the four-dimensional combination of space (three dimensions) and time (the fourth dimension). As a consequence of Special Relativity, time and space are not independent of each other and are relative to the motion of an observer.

A system of one time and three spatial coordinates, with respect to which the time and place of an event can be specified.

the four-dimensional Universe suggested by general relativity

The mathematical construct representing the arena of events. Since the theory of relativity it has been recognized that space and time cannot be separated, with time then becoming the fourth dimension of our Universe.

The four-dimensional continuum in which the events of the universe take place. According to relativity, spacetime breaks down into space and time in different ways for different observers.

A synthesis of the three dimensions of space and of a fourth dimension, time; a hallmark of relativity theory.

The four-dimensional coordinate system (three dimensions of space and one of time) in which physical events are located.

In physics, spacetime is a mathematical model that combines space and time into a single construct called the space-time continuum. Spacetime is usually interpreted as a four-dimensional object with space being three-dimensional and time playing the role of the 4th dimension. According to Euclidean space perception, our universe has three dimensions of space, and one dimension of time.