The region of the universe beyond Earth's atmosphere. ◇ The part of this region within the solar system is known as interplanetary space. ◇ The part of this region beyond the solar system but within the Milky Way or within another galaxy is known as interstellar space. ◇ The part of this region between the Milky Way and other galaxies is known as intergalactic space.
The familiar three-dimensional region or field of everyday experience.
Mathematics A mathematical object, typically a set of sets, that is usually structured to define a range across which variables or other objects (such as a coordinate system) can be defined.