The basic unit of which the dimensions of parts of a work are multiples. The principle of the module is used in sculpture and other mediums, but is most often seen in architecture. For example, in a building the module may be the width of a column, and other elements, such as the height of the columns or the spaces between the columns,  may be planned as whole-number multiples of that module.

Analytical drawing of the façade of the church of Sta. Maria Novella, Florence, showing the use of the column width as a module.