How parts mate together is referred to as what?

The term that best describes how parts fit together is "fit." In aerospace assembly, fit refers to the precise relationship between two or more components, indicating how closely they conform to each other's dimensions and tolerances. Proper fit is critical to ensure structural integrity, functionality, and performance of the assembly. Different levels of fit, such as clearance fit, interference fit, and transition fit, determine how tightly parts will interface with one another.

Understanding fit is essential in aerospace mechanics because it can significantly impact the assembly process and the overall reliability of the finished product. A correct fit helps to prevent issues related to wear, stress concentration, and failure during operation. Hence, "fit" encompasses the concept of how well parts align and work together as intended.