**Space** is the undefined and unbounded entity that contains all material things. These, having an extension, occupy a part of it and assume a position in space, which is defined quantitatively according to the principles of geometry, and qualitatively, according to relationships of proximity (distance) and size (smallness).

Real physical space is believed to be three-dimensional, although in modern physics such three-dimensional space is considered to be part of a four-dimensional continuum called space-time, which also includes time. In mathematics they can be defined as “spaces” with even more than four dimensions, and with complex underlying structures. Experimental observations so far confirm the hypothesis of a three-dimensional space up to subatomic dimensions. High energy physics, and in particular the experiments at the Large Hadron Collider at CERN, search for possible manifestations of extradimensions on subatomic scales.

The concept of space is considered of fundamental importance for understanding the physical universe, and the properties attributed to it are related to everyday observations and experiences of objects around us. However, there is ongoing disagreement among philosophers as to whether it is itself an entity, a relation between entities, or part of a conceptual framework.

Our own biological constitution has led us to a representation of the Universe that makes it natural for us to consider space and the bodies in it separately. This concept of space allows a convenient description of many properties of objects, such as the length of a segment, the distance of two points, the area of a surface, the volume enclosed by a surface, angles, the position of a point with respect to another, etc. All these geometric properties of objects can be transferred to space as its properties, independent of the objects. All these geometric properties of objects can be transferred into space as its own properties, independent of the specific objects, and a precise description of what is called three-dimensional or Euclidean is achieved.

As the common concept of three-dimensional space, i.e. of the ordinary, is foreign to a born blind, so it proves inadequate when studying phenomena that occur on a scale immensely larger than human scale, such as the space where collisions of galaxies occur, or immensely smaller, as in atomic physics, nuclear physics or physics of fundamental particles. On the one hand, in the description of phenomena in the immensely large, Einstein’s theory of relativity criticizes and abandons the concept of Euclidean space; on the other hand, quantum mechanics puts limits to our ability to describe phenomena on atomic and subatomic scale and introduces concepts different from the classical ones. For example, the space considered in the theory of relativity is called Minkowski space-time, or chronotope, or four-dimensional.

## Lexicon

In the philosophical and scientific sense, space (14th century; from Latin *spatíum*) is an unlimited and indefinite entity in which sensible bodies are contained and move: man cannot imagine anything outside the and time. In the common understanding, the place outside the Earth’s atmosphere in which celestial bodies move: the cosmic; launch a rocket in the; the heroes of the , the first astronauts. For the history of the conquest and exploitation of space, understood in this sense, see Astronautics.

A more or less extensive but limited area, circumscribed by various elements taken as a point of reference, in which a body is or can be placed:

- the space of a room, of an apartment; I need space to work;
- air space, that which is limited by the imaginary vertical extension of state borders;
- public space, that which lies below or above a public space, such as a street or a square, and the use of which is subject to a tax;
- living space, in the Nazi concept, the living space in which the “Aryan race” was to develop; in a broader sense, often jokingly, the space and complex of means necessary to do something, to achieve one’s goals: a child full of complexes because it lacks the vital at home.

Extent of an area; territory: the forest extends over a large area. In a newspaper, book, etc., the part of the page or pages intended for printing: your article takes up too much space. By extension, in a speech, etc., the time devoted to a subject: devote enough time to a problem.