# Definition:Ordinary Space

## Definition

Ordinary space (or just space) is a word used to mean the universe we live in.

The intuitive belief is that space is $3$-dimensional and therefore isomorphic to the real vector space $\R^3$.

Hence ordinary space is usually taken as an alternative term for Euclidean $3$-dimensional space.

## Also known as

Ordinary space can also be referred to as physical space but that term is also used in common parlance to mean a particular volume for day-to-day deployment of stuff.

I would love to take my entire collection of cuddly toys on holiday with me to St. Petersburg, but I don't have the physical space in my suitcase.

In a wider sense, the term natural world can be used.