Interchangeable parts, the ability to select components for assembly at random and fit them together within proper tolerances
An early leader was Jean-Baptiste Vaquette de Gribeauval, an 18th-century French artillerist who created a fair amount of standardization of artillery pieces, although not true interchangeability of parts.
This allowed the concept of interchangeability (an idea that was already taking hold) to be practically applied to nuts and bolts.
New York designer Gilbert Rohde crafted several lines of modular casework for the Herman Miller Corporation in the 1930s and 40s; like De Koninck, Rohde standardized the units in dimensions, materials and configurations to facilitate mass production and interchangeability.
In the late 18th century and throughout the 19th, the American and French militaries were early adopters and longtime developmental sponsors and advocates of interchangeability and standardization.