What is a keyboard trap?

Question

Can you help define what a keyboard trap is for me?

Answer

Just as keyboard users must be able to navigate to all interactive elements on a page with only the keyboard, they must also be able to navigate away from these elements with the keyboard. When they are not able to do so, that is called a keyboard trap. For example, if a user tabs to a button that opens a modal but the user is not able to exit out of that modal, they've hit a keyboard trap.