Is identity certificate same as public key?


I’m new to public key infrastructure. I think I understand how public key encryption works, conceptually. So public key is, by definition, public and not a secret. Recently when I came across the term identity certificate and read about it, it sounded very similar to public key of an entity. But, it was not explicitly stated whether they are same or different.

My questions are…

Is identity certificate same as public key? If no, then is identity cert considered a secret?

How are they related?