# Door **Domain:** Architecture / Access / Governance **Doc Type:** Material Interface Node **Maturity:** Developed ## Definition A **door** is a movable architectural boundary that converts enclosure into conditional passage. It is the smallest common building mechanism through which inside and outside become operational states rather than abstract distinctions. ## Governing Variable The door governs passage. Its width, hardware, visibility, direction of swing, locking state and credential requirements determine who can cross, in which direction and under what conditions. ## Material and Institutional Manifestation A domestic door protects privacy; a fire door manages smoke and required egress; an automatic door changes accessibility; a secure door binds identity to entry. The same object can be an invitation, a delay, a safety device or a denial. ## Computational Analogue Authentication gates, API gateways and policy checks perform structurally similar work by converting a boundary into a conditional transition. The analogy is especially direct when a physical door is connected to credentials, event logs and a building control system. ## Constitutional Question and Failure Modes Who sets the condition for opening, who can override it and whether exit remains possible are constitutional questions in miniature. Failure can mean unauthorized entry, inaccessible passage, entrapment or a record that treats a person as absent because a credential failed. ## Related Ontology [[wiki/Enclosure|Enclosure]] · [[wiki/Threshold|Threshold]] · [[wiki/Access Geometry|Access Geometry]] · [[wiki/Building Code|Building Code]] · [[wiki/Cyber-Physical Enclosure|Cyber-Physical Enclosure]]