Tribology is the study of friction, wear, and lubrication between surfaces in contact. It introduces key concepts like viscosity, lubricants, and different regimes of lubrication. Viscosity is important for a fluid's ability to carry loads as friction is converted to heat. Different instruments can be used to measure viscosity, like viscometers that determine damping effects on an oscillating resonator immersed in the fluid. Tribology is important because lubricants allow objects to move with low friction and prevent wear.