A spinner is an aircraft component, a streamlined fairing fitted over a propeller hub or at the centre of a turbofan engine. Spinners both make the aircraft overall more streamlined, thereby reducing aerodynamic drag, and also smooth the airflow so that it enters the air intakes more efficiently. Spinners also fulfill an aesthetic role on some aircraft designs.[1][2][3]
^Crane, Dale: Dictionary of Aeronautical Terms, third edition, page 480. Aviation Supplies & Academics, 1997. ISBN1-56027-287-2