in Ancient Architecture, the front door of a house, called also jambus, and in Greek by the several terms ἀπόστημα, ἀπόστημα, ἀπόστημα. The back door in Roman houses was called posticum, postica, or posticula, in Greek παράθυρον or παραθύρων; and Cicero (Post Red. 6) uses pseudothyron in contradistinction to jambus. It was accounted ominous to set the left foot on the threshold; hence the steps of a temple were of an uneven number, so that by commencing the ascent with the right foot, the danger would be avoided. (See Vitruvius, iii. 4.) The door of a temple was called foris and valva, in Greek σκόπις, σκόπιος, or θήρα, these words being generally used in their plural form to denote the two halves of a folding-door. Bivalve doors were also used in private apartments.