Yes, Lean and Six Sigma are two separate methodologies used to improve processes. They originated in different places and at different times.
Lean’s main focus is eliminating waste to streamline processes. Six Sigma aims to reduce variation and “problem solve” by identifying and eliminating flaws.
They are extremely powerful when used together, and they are frequently combined for a more thorough and sustainable process improvement. Therefore, the term “Lean Six Sigma” is widely used.