Waste in Lean is known as the three Ms—muda (waste), mura (unevenness), and muri (overburden).  Mura refers to variations or inconsistencies in a process; muri concerns overburden or unreasonableness in a process.
Muda is further divided into eight forms of waste:
Motion—unnecessary movement of people
Waiting—people waiting for people, information, products, equipment, etc.
Movement—unnecessary movement of "things"
Correction—incomplete or incorrect information
Over Processing—doing more than necessary to produce a product or service
Overproduction—doing or making more than needed
Inventory—excess supplies, paperwork, information or equipment
Knowledge—not utilizing an individual's full capacity (knowledge, skills, aptitude and/or creativity)