circulator

/S ER1 K Y AH0 L EY0 T ER0/
noun
  1. 1

    A person or thing that causes something to circulate

  2. 2

    (transport) A local transit system that provides regular service within a closed loop

  3. 3

    (electronics) A passive electronic component with three or more ports, in which the ports can be accessed in such a way that when a signal is fed into any port it is transferred to the next port only