porthole

nouns

a window in a ship or airplane
is a part of
the central body of an airplane that is designed to accommodate the crew and passengers (or cargo)
is a part of
a vessel that carries passengers or freight
is a type of (narrower)
a framework of wood or metal that contains a glass windowpane and is built into a wall or roof to admit light or air
an opening (in a wall or ship or armored vehicle) for firing through