An aisle is the lower space that runs parallel to the nave of a church or basilica, separated from it by a row of columns or piers. Churches usually have two aisles (left and right of the nave), but large cathedrals may have four or more.
Characteristics of an aisle
| Characteristic | Description |
|---|---|
| Position | Alongside the nave, parallel to the longitudinal axis |
| Height | Lower than the nave |
| Separation | Columns or piers with arches (arcade) |
| Width | Narrower than the nave |
Function of the aisle
- Processional route: space for processions during church ceremonies
- Extra capacity: additional room for the congregation
- Side chapels: niches or chapels in the outer wall of the aisle
- Structural support: the aisles support the higher nave via the arches
Types of church plans
| Type | Number of aisles |
|---|---|
| Hall church (no aisles) | None (single space) |
| Three-aisled church | 2 aisles (left and right) |
| Five-aisled church | 4 aisles |
| Hall church (equal height) | Aisles the same height as the nave |
| Basilica | Aisles lower than the nave |
Structural role
The aisles play an important role in the stability of the building:
- The aisle roofs absorb the lateral thrust from the nave
- In Gothic churches: flying buttresses transfer the forces over the aisles to the buttress piers
- The height difference between nave and aisle makes clerestory windows possible
Related terms
- Nave: the central, tallest space of the church
- Transept: the cross arm of a cruciform church
- Crossing: the intersection of nave and transept
- Arcade: the row of arches separating nave and aisle
- Clerestory: the window zone above the arcade