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.
Definition 2 example: The dimensions in question in the formula for speed are distance and time.
Definition 3 example: In this other dimension, the strange people with giant hands did things vastly differently.