Merriam-Webster Online Dictionary
aisle (noun)1.
the side of a church nave separated by piers from the nave proper
2.
a) (1) a passage (as in a theater or railroad passenger car) separating sections of seats
(2) such a passage regarded as separating opposing parties in a legislature - supported by members on both sides of the aisle
b) a passage (as in a store or warehouse) for inside traffic