A collection of pages, organized together into one hierarchical unit.

As described by Atlassian, spaces are "Confluence's way of organizing content into meaningful categories." In practical terms, a space is made up of one or more pages, organized hierarchically in one or more page trees. Spaces have both space names and space keys. Note that while space names can be changed at any time, a space key cannot be changed after creation.

Being thoughtful about how content is organized allows you to apply space-level settings, such as permissions and styling, in meaningful and useful ways.