Engaged column
In architecture, an engaged column is a column embedded in a wall and partly projecting from the surface of the wall, sometimes defined as semi or three-quarter detached. Engaged columns are rarely found in classical Greek architecture, and then only in exceptional cases, but in Roman architecture they exist in abundance, most commonly embedded in the cella walls of pseudoperipteral buildings.
Engaged columns serve a similar function as wall buttresses but are distinct from pilasters, which by definition are ornamental and not structural.
See also
Decastyle
Hexastyle
Hypostyle
Octastyle
Peristyle
Portico
Tetrastyle
References
Stierlin, Henri The Roman Empire: From the Etruscans to the Decline of the Roman Empire, TASCHEN, 2002
This article incorporates text from a publication now in the public domain: Chisholm, Hugh, ed. (1911). Encyclopædia Britannica (11th ed.). Cambridge University Press.