In a strict sense: Space as we know it from everyday life: the totality of all locations in which objects can sit, with three dimensions.

In a more general sense used by mathematicians, all kinds of sets of points are spaces – a line for instance, which has but a single dimension, or a two-dimensional surface, but also higher-dimensional spaces. Also, in such more general spaces, geometry can be different from the standard Euclidean geometry taught in high schools – such spaces can be curved.