Definition of "fantail"

Any of several birds, of the genus Rhipidura, from Asia, Australia and New Zealand.  examples

Any of several domestic varieties of pigeon having a fan-shaped tail.  examples

Any of several goldfish having a large fan-shaped tail.  examples

(nautical) An overhanging deck at the stern of a ship.  quotations  examples

A small windmill mounted at right angles to the sails, at the rear of the windmill, used to turn the cap automatically to bring it into the wind.  examples

A brimmed hat with just the back of the brim turned up.  examples