User login with 3rd party services and email/password

1. What does 3rd party login mean?
2. What is third party access on Google Account?
3. What is a third party password?

What does 3rd party login mean?

Third-party login is an authentication alternative used by several websites that allow you to access from an existing social media profile account on Google, LinkedIn, or Facebook without having to define a new username and password.

What is third party access on Google Account?

To help you safely share your data, Google lets you give third-party apps and services access to different parts of your Google Account. Third-party apps and services are created by companies or developers that aren't Google. For example, you may download an app that helps you schedule workouts with friends.

What is a third party password?

Basically, it just means that instead of using your iCloud email and password, it uses a password that third party apps will store and use instead.