# Shared ontologies

A shared ontology is a special kind of ontology that allows multiple [organizations](../../security/orgs-and-spaces/index.md#organizations) to collaborate on shared workflows. Shared ontologies live under a dedicated shared [space](../../security/orgs-and-spaces/index.md#spaces) created specifically for the workflow. A shared ontology enables resources from multiple organizations to be used in a workflow, whereas an ontology is private to one organization and contains resources from that organization alone.

A shared ontology is automatically created when a new shared space is created. It holds the same organization [markings](../../security/markings/index.md) and [role grants](../../security/projects-and-roles/index.md#roles) as the shared space.

To help you decide whether a workflow needs a shared ontology or a private one, review the [examples comparing private and shared ontologies](../ontologies-overview/index.md#private-vs-shared-ontologies).

See [cross-organization collaboration](../../security/cross-organization-collaboration/index.md) for more details on how to set up secure collaborative workflows.