Why is it called pull request and not push request

A "pull request" is you requesting the target repository to please grab your changes. A "push request" would be the target repository requesting you to push your changes. When you send a pull request, you're asking (requesting) the official repo owner to pull some changes from your own repo. Hence "pull request".

En consecuencia, why is it called a pull request?

When you're ready for feedback, submit a pull request. Pull requests are a feature specific to GitHub. They provide a simple, web-based way to submit your work (often called “patches”) to a project. It's called a pull request because you're asking the project to pull changes from your fork.

En consecuencia, what is the difference between pull and pull request?

If you use git pull , you pull the changes from the remote repository into yours. If you send a pull request to another repository, you ask their maintainers to pull your changes into theirs (you more or less ask them to use a git pull from your repository).

Pero entonces, what is GitHub pull request?

Pull Requests are the heart of collaboration on GitHub. When you open a pull request, you're proposing your changes and requesting that someone review and pull in your contribution and merge them into their branch. Pull requests show diffs, or differences, of the content from both branches.