Six Sigma is a data-driven methodology aimed at process improvement by eliminating defects, originally developed by Motorola in the 1980s. It utilizes structured methods like DMAIC and DMADV to enhance business processes and ensure quality, ultimately increasing customer satisfaction and profitability. The approach involves various roles, including trained 'black belts' and 'green belts', and employs numerous analytical tools to support problem-solving and performance measurement.