Dimensional tolerance refers to the permissible limits of variation in a physical dimension of a part or assembly. It ensures that components fit together correctly and function as intended, even if there are slight differences in size or shape during manufacturing. This concept is crucial in fields like engineering and manufacturing, where precision is essential. Tolerances are typically specified in engineering drawings using symbols and numerical values. They can be classified into two main types: geometric tolerances, which control the form and orientation of features, and linear tolerances, which focus on the size and location of dimensions. Properly defined tolerances help maintain quality and reduce production costs.