According to the National Institute of Standards and Technology (NIST), which cloud computing deployment model...

According to the National Institute of Standards and Technology (NIST), a hybrid cloud is a cloud computing deployment model that describes a composition of two or more distinct cloud infrastructures (private, community, or public) that remain unique entities but are bound together by standardized or proprietary technology that enables data and application portability. Hybrid clouds allow organizations to leverage the advantages of multiple cloud environments, such as combining the scalability and cost-efficiency of public clouds with the security and control of private clouds. This model facilitates flexibility and dynamic scalability, supporting diverse workloads and business needs while ensuring that sensitive data and applications can remain in a controlled private environment.

References

NIST Definition of Cloud Computing

Hybrid Cloud Overview and Benefits