<aside> tag OR <section> tag

Question

It says in a lesson that <aside> tag can be used within <article> tag.

"When an <aside> tag is used within an <article> tag, the content of the <aside> should be specifically related to that article."

Why isn't the <section> tag used for that purpose? Shouldn't the aside element used only in the outside of the <article> tag? If <aside> and <section> tags can be used both within and outside of the <article> tag then what makes them different?

Answer 1

There is no difference between them besides the differing names. All of them are block elements, just like a div.