a structure that runs lengthways along the centre of the bottom of a ship or boat and that often projects downward to improve stability
a structure that runs lengthways along the centre of the bottom of a ship or boat, from which the framework of the hull is built up, and that often projects downward to improve stability
the main load-bearing member, e.g. in an airship or aeroplane
a projection or ridge suggesting a keel, e.g. the breastbone of a bird or a pair of linked flower petals
without any sudden changes or trouble; steady; calm