noun

• A wing of a building, notably in a church separated from the nave proper by piers.
• A clear path through rows of seating.
• A clear corridor in a supermarket with shelves on both sides containing goods for sale.
• Any path through an otherwise obstructed space.
• (transport) Seat in public transport, such as a plane, train or bus, that's beside the aisle.
• (US, politics) An idiomatic divide between the Republican Party and the Democratic Party, who are said to be on two sides of the aisle.
• The path of a wedding procession in a church or other venue; (by extension, metonymically) marriage.