GD&T (Geometric Dimensioning and Tolerancing) is a symbolic language used on engineering drawings to define the shape, size, orientation, and location of features with precision. Unlike basic dimensions and tolerances, GD&T allows engineers to communicate functional requirements and manufacturing limits clearly—ensuring parts fit and work together even with variations. It helps reduce errors, improve quality, and enhance interchangeability in CNC machining, inspection, and assembly. Mastering GD