Difference between Web driver, Remote Web Driver and Chrome Driver

Webdriver

Web driver is interface.
Global for all browsers
The interface provide common methods signature for all browser.
Ex : findElement(), get(),switchTo()

Remote Webdriver

Remote Webdriver is concrete class  implements Webdriver.
The implementation of webdriver method is available  in Remote Webdriver Class.
The Class provide additional  method  which is not available in webdriver. Provide method to run selenium test in remote machine.
ex : getSessionID()


Chrome driver

Chrome Driver is class extends Remote Webdriver.
Only specific to Chrome browser.
The class have implementation for only chrome browser.