Leonardo da Vinci’s birdlike flying-machine concept is an ornithopter.
An ornithopter is an aircraft intended to fly by flapping wings, rather than by using fixed wings or a helicopter rotor. Leonardo studied birds and bats closely and made several sketches exploring how a person might power artificial wings with arms, legs, or mechanical linkages.
His drawings were important as studies of flight, but they did not produce a practical aircraft. A human pilot could not supply enough sustained power through the proposed mechanisms, and the weight of the frame and wings would have made controlled flight extremely difficult. Modern ornithopters do exist as small experimental or model aircraft, usually powered by motors.
The word is broader than Leonardo’s work: it describes a whole class of flapping-wing aircraft. Leonardo’s particular designs are therefore examples of ornithopters, not a single completed machine.