A helicopter is an aircraft with long blades on top that go round very fast. It is able to stay still in the air and to move straight upwards or downwards.
helicopter in British English
(ˈhɛlɪˌkɒptə)
noun
1.
an aircraft capable of hover, vertical flight, and horizontal flight in any direction. Most get all of their lift and propulsion from the rotation of overhead blades
See also autogiro
verb
2.
to transport (people or things) or (of people or things) to be transported by helicopter
Word origin
C19: from French hélicoptère, from helico- + Greek pteron wing
helicopter in American English
(ˈhɛlɪˌkɑptər)
noun
1.
a kind of vertical-lift aircraft, capable of hovering or moving in any direction, havinga motor-driven, horizontal rotor