It is a deployment model where the application is deployed partially on-premises and partially in the cloud or some other off-premises environment.
In a hybrid deployment model, certain components of the application may be deployed on-premises, while others may be deployed in a public or private cloud. This approach allows organizations to take advantage of the benefits of both on-premises and cloud-based environments.
One common use case for hybrid deployment is when an organization has sensitive or critical data that must remain on-premises for security or compliance reasons, but the organization still wants to take advantage of the scalability, flexibility, and cost savings offered by cloud computing.