A vestibule is a small room leading into a larger space such as a lobby, entrance hall, or passage, for the purpose of waiting, withholding the larger space from view, reducing heat loss, providing storage space for outdoor clothing, etc. The term applies to structures in both modern and classical architecture since ancient times.

In ancient Rome, the domus was the type of town house occupied by the upper classes and some wealthy freedmen during the Republican and Imperial eras. It was found in almost all the major cities throughout the Roman territories. The modern English word domestic comes from Latin domesticus, which is derived from the word domus. Along with a domus in the city, many of the richest families of ancient Rome also owned a separate country house known as a villa. Many chose to live primarily, or even exclusively, in their villas; these homes were generally much grander in scale and on larger acres of land due to more space outside the walled and fortified city.