a person who exercises control or authority; specif somebody who directs or supervises workers

a politician who controls a party organization, e.g. in the USA

to act as director or supervisor of (the staff of an organization, etc)

(usu + about/around) to give orders to (somebody) in a domineering manner

a stud or knob projecting from the centre of a shield

a carved ornament concealing the intersection of the ribs of a vault or panelled ceiling

the enlarged part of a shaft, on which a wheel is mounted

the middle part of a propeller

a rounded mass of igneous rock protruding through other layers

a protuberant part; a prominence