Points are defined by three values of magnitude X, Y, Z for example 100mm, 240mm, 345mm. They maybe the simplest geometry form but points are the underpinning geometry for everything else.
For example a line is define by two points, a vector is defined by two points (one is always at 0,0,0), planes are defined by a point and a vector (defined by a point). We can keep expanding out into Bezier curves and basic 3D geometry’s as well so the humble point is quite interesting.