What is Black Box Testing? Are Functional and Usability Testing its types?

I am writing about testing and I am confused about the following:

What is Black Box Testing? Are Functional and Usability Testing its types?

I am writing about testing and I am confused about the following:

What is Black Box Testing? Are Functional and Usability Testing its types?

I am writing about testing and I am confused about the following:

What is Black Box Testing? Are Functional and Usability Testing its types?

I am writing about testing and I am confused about the following:

What is Black Box Testing? Are Functional and Usability Testing its types?

I am writing about testing and I am confused about the following: