gyratory
Concise Oxford English Dictionary © 2008 Oxford University Press:
gyratory /dʒʌɪˈreɪt(ə)ri, ˈdʒʌɪrət-/
▶adjective of or involving circular or spiral motion. ▶noun (pl. gyratories) a traffic system requiring the circular movement of traffic.
'gyratory' also found in these Oxford entries:

