A hybrid cloud is one that utilizes both public and private clouds.
This is ideal for companies that are multi-faceted, where they can take advantage of the positives that both public and private clouds offer.
As a private cloud provides an extra level of security and better performance, while a public cloud is cheaper and more scalable, individual operations can be placed on the cloud that makes the most sense. Those that use a hybrid cloud service typically place all of their essential data on a private cloud, while non-sensitive operations are taken care of on the public cloud.
An example of this could be a business that is hosting their e-commerce website on a private cloud for that added level of security and performance, but using a public cloud for their blog where security isn’t as much of a concern (and it is also more cost effective).
In essence, it is the combination of what makes both public and private cloud hosting a popular choice among businesses. The best of both worlds you could say.