Aisles, exits, and egress are all part of a building's means of egress, which is the unobstructed path to leave a building

 Aisles, exits, and egress are all part of a building's means of egress, which is the unobstructed path to leave a building: 

Aisle

An unenclosed exit access component that provides a path of egress travel. Aisle accessways are paths between rows of seats or tables that lead to aisles. 

Exit

A component of the means of egress that leads from the floor area to a separate building, open public thoroughfare, or exterior open space. Exit components include exterior exit doors, interior exit stairways and ramps, and exit passageways. 

Egress

The continuous and unobstructed path of vertical and horizontal travel from any occupied portion of a building to a public way. The means of egress is made up of three parts: exit access, exit, and exit discharge. 

Some requirements for means of egress include:

Ceiling height: At least 7 feet 6 inches (2286 mm) above the finished floor

Protruding objects: No more than 50% of the ceiling area can be reduced in height by protruding objects

Elevators, escalators, and moving walks: Not used as a component of a required means of egress