A lean manufacturing framework, which emphasises on the idea of providing value to the customer in less work, was given by Taiichi Ohno, the father of Toyota Production System. He suggested that anything that doesn’t add value in the eye of the customer is a waste (“Muda” in Japanese) and every effort should be made to eliminate that waste. The following 8 components of waste, though initially introduced in Lean Manufacturing system, have universal application; be it any industry or domain.
There are two famous acronyms used to remember these 8 wastes- one is TIMWOODS (Transportation, Inventory, Motion, Waiting, Overproduction, Over-processing, Defects, Skill’s underutilization). The other is DOWNTIME, which stands for Defects, Overproduction, Waiting, Non-utilized skills, Transportation, Inventory, Motion and Extra processing.
Find a good detailed explanation of each of this type of waste here.