What is meant by the term 'first responder' and how is it used in systems or applications?

In iOS, the term "first responder" refers to the object that first receives input events, such as touches, key presses, and other user interactions.

The first responder is part of the responder chain, which determines the order in which events are passed between objects.

For example, when a user taps on a text field, it becomes the first responder and starts receiving keyboard events.

This allows managing input focus and handling events by the object that is currently active.

To make an object the first responder, the following method is called:

textField.becomeFirstResponder()

And to relinquish this status:

textField.resignFirstResponder()

Thus, the first responder plays a key role in processing user input and interacting with the interface.