Illustrated Companion to the Latin Dictionary/Prothyrum

This article incorporates text from a publication now in the public domain: Rich, Anthony (1849). The illustrated companion to the Latin dictionary, and Greek lexicon. p. vi. OCLC 894670115. https://archive.org/details/illustratedcompa00rich. 

PROTH'YRUM (διάθυρον). An entrance hall in a Roman house; that is, a small corridor situated between the street door (janua), which was probably always kept open in the day-time, as is still the practice of modern Italy, and the house door (ostium), which gave immediate access to the atrium, and interior of the house. The Greek name defines it more accurately as the part between (διά) the doors; and their πρόθυρον, or place before the door, corresponds with the Roman vestibulum (Vitruv. vi. 7. 5.). The woodcut (Prothyrum/1.1) represents an entrance-passage to one of the houses at Pompeii, with the ceiling and doors restored to give a more complete notion of the locality; the columns seen through the furthest door, one leaf of which is represented as closed, are those of the atrium.

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  Prothyrum/1.1