Lean Philosophy

A mindset, belief, or culture toward continuously improving every aspect of a process or operation to make it more efficient (i.e., improving time, effort, cost or flow). Lean is considered a philosophy as opposed to a methodology because it's not based on a set of sequential steps, but is a way of thinking that focuses on identifying and eliminating waste in a process. A common mindset is that no process is 100% perfect, so there is always opportunity for improvement even at the seemingly small, insignificant level.
Related StatStuff Video: 
   -Section 2-Lean, Lesson #1 - Introduction to Lean