1. a place (seaport or airport) where people and merchandise can enter or leave a country
2. sweet dark-red dessert wine originally from Portugal
3. an opening (in a wall or ship or armored vehicle) for firing through
4. the left side of a ship or aircraft to someone facing the bow or nose
5. (computer science) computer circuit consisting of the hardware and associated circuitry that links one device with another (especially a computer and a hard disk drive or other peripherals)