Corridors—transitional, purely functional spaces—seem a ubiquitous architectural feature in offices, subway systems and many homes. This, however, was not always the case.

The word derives from the Spanish corredor (runner), messengers in 14th-century Spain for whom nobles built passageways that would expedite their journeys. Elsewhere in Europe, in palaces like Versailles or large public buildings, rooms were not connected to or separated from each other with corridors. Rather, they were designed as enfilades—suites in which one room led directly into another.

Enfilade’s second meaning—in combat, being attacked from the vulnerable, more exposed flank position—is a fitting metaphor for the classist obsession with corridors in 19th-century Britain. “In country homes, there ...