Haptics refers to the science and technology of touch perception [our ability to sense physical contact with our surroundings]. It involves the use of tactile feedback [sensations of touch] to communicate with users through a device or interface. Haptics can be found in everyday technology, such as the vibrations on a smartphone or the force feedback in a gaming controller.
For example, when you receive a call on your smartphone, the device may vibrate to provide haptic feedback. Another example is the vibration feedback you feel when pressing the keys on a touch screen keyboard.
Very Simple Definition:
Haptics is the science of touch. It’s used in technology to make things feel different [like a vibration in a phone or a controller that shakes in your hand].