1. dimension (n) pl. dimensions: A specification of the spatial and
directional limits of a given space, designated by a number representing the maximum number of lines in said instance of geometric space that can possibly exist such that the angle between any one of them and any other one of them is a
right angle (also designated by the minimum number of points needed to define it
minus one).
2. dimension (n) pl. dimensions: A category of related units of measurement that can be converted to one another from one another.
3. dimension (n) pl. dimensions: An alternate universe or a parallel universe, the latter usually referred to in fiction.