Vibrate on touch / Haptic feedback
Haptic feedback is a feature whereby interacting with some buttons on the screen will result in a subtle but noticeable "jolt" or "vibrate" by the phone. This is produced using the vibration feature of the phone.
The intention of haptic feedback is to act as tactile feedback that a button has been pressed, as a substitute for the sort of "click" feel that a physical button or key might have had, but touch screens do not have.
Haptic feedback, if enabled, usually only works on certain on-screen keys or buttons.
Haptic feedback can increase battery usage, and turning it off may improve battery life.