Final answer:
The longitudinal divisions of a church, separated from the nave by columns or piers, are called aisles, allowing visitors to move through without disturbing ongoing masses.
Step-by-step explanation:
The longitudinal divisions of a church, separated from the nave by a row of columns or piers, are known as aisles. Aisles are auxiliary passageways that allow movement throughout the church, enabling visitors to partake in activities such as a pilgrimage or mass without causing disruptions. As an integral interior element of church architecture, aisles are typically found on either side of the central nave, which is the main and prominent aisle running longitudinally through the church.