In terms of time and space, a "point" can be defined as an infinitesimally small and dimensionless location. It represents a specific position in both time and space. Let's break down the definition in relation to each dimension:
Space: In three-dimensional space, a point has zero dimensions and occupies no physical extent. It is often represented as a dot or a geometric abstraction with no size, such as a mathematical coordinate (x, y, z) or a position vector. A point in space specifies its location in terms of its coordinates or relative distance from a reference point.
Time: In the context of time, a point represents an exact moment or an instant. It does not have duration or extension but denotes a specific time coordinate. For instance, a point in time could be defined by a particular date, hour, minute, and second.
When combining both space and time, a point in spacetime is a coordinate that indicates both the position and time of an event in a four-dimensional framework. This concept is fundamental in the theory of relativity. However, in everyday life and most practical applications, we typically treat space and time separately, simplifying our understanding of points to specific locations or moments.