porticus
/ˈpɔːtɪkəs/noun
1 Architecture. A formal entrance to a classical temple, church, or other building, consisting of columns at regular intervals supporting a roof often in the form of a pediment; a covered colonnade in this style.
2An aisle or transept on the north or south side of an Anglo-Saxon church, containing a chapel. historical.
Origin
Early 17th century; earliest use found in Fynes Moryson (?1566–1630), traveller and writer. From classical Latin porticus colonnade, arcade, porch, specifically the colonnade at Athens in which Zeno used to teach, sometimes used as a symbol of Stoic philosophy, in post-classical Latin also side-chapel from porta + -icus.