Aisle (#), n. [OF. ele, F. aile, wing, wing of a building, L. ala, contr. fr. axilla.] Arch. (a)
A lateral division of a building, separated from the middle part, called the nave, by a row of columns or piers, which support the roof or an upper wall containing windows, called the clearstory wall.
Improperly used also for the have; -- as in the phrases, a church with three aisles, the middle aisle.
Also (perhaps from confusion with alley), a passage into which the pews of a church open.
© Webster 1913.