[German version]

(Lat. 'slat', 'bar', or 'guideline'). Architectural technical term used in Vitr. De arch. 4,3,4 et alibi to refer to a slat with guttae on the epistylion (architrave) of a building of Doric structure. In width, the regula corresponds to the triglyphos and forms its lower end which structurally belongs to the architrave (and not to the frieze). Furthermore, the regula corresponds to the blocks of the geison that are resting on the frieze.

Höcker, Christoph (Kissing)