teclado del órgano de expresión
/teklˈaðo ðel ˈoɾɣano ðe ˌekspɾesjˈon/
n
English: swell organ manual · 强弱音键盘
Significado：Keyboard that controls a series of pipes enclosed in a wooden frame (swell box); its movable valves are controlled by a swell pedal to obtain variations in volume.