Henotheism is like having a favorite superhero. You might still think the other superheroes are cool, but you really admire and worship just one of them.
In the same way, henotheism is when people believe in lots of different gods, but they worship and follow just one particular god as the most special or powerful one.
For example, some ancient Egyptians believed in many gods for different things like the sun, the Nile River, or fertility, but they might have worshipped the god Horus more than the others because they thought he was the most important.
Henotheism is different from monotheism, where people believe in only one god, and polytheism, where people believe in lots of gods equally without favoring any of them.