Button-downs are a type of shirt that have a collar and buttons down the front. They are usually made of cotton or linen and are often worn with a tie. The term 'button-down' comes from the fact that the shirt's collar is secured to the shirt with buttons. Keystrokes are the physical actions of pressing keys on a keyboard in order to input data into a computer. Keystrokes are used to type words, numbers, and symbols into a computer.