Definition of flutter noun from the Oxford Advanced American Dictionary
flutter
noun
/ˈflʌt̮ər/
1[countable, usually singular]a quick, light movementthe flutter of wingswith a flutter of her long, dark eyelashes(figurative)to feel a flutter of panic in your stomach2[singular]a state of nervous or confused excitementHer sudden arrival caused quite a flutter.to be in a flutter3[countable]a very fast heartbeat, caused when someone is nervous or excitedHer heart gave a flutter as she went out on stage.4[uncountable](medical)a medical condition in which you have a fast, unsteady heartbeat5[uncountable](technical)rapid changes in the pitch or volume of recorded sound compare wow