WordNet sense 1 (a toroidal shape):

doughnut, halo, annulus, anulus, anchor ring

WordNet sense 2 ((chemistry) a chain of atoms in a molecule that forms a closed loop):

closed chain

WordNet sense 3 (an association of criminals):

mob, pack

WordNet sense 4 (the sound of a bell ringing):

ringing, tintinnabulation

WordNet sense 5 (jewelry consisting of a circlet of precious metal (often set with jewels) worn on the finger):

band

WordNet sense 6 (a rigid circular band of metal or wood or other material used for holding or fastening or hanging or pulling):

hoop

WordNet sense 7 (be around):

circle, encircle, round, surround, environ

WordNet sense 8 (ring or echo with sound):

echo, resound, reverberate, resound

WordNet sense 9 (make (bells) ring, often for the purposes of musical edification):

knell

WordNet sense 10 (sound loudly and sonorously):

peal

WordNet sense 11 (get or try to get into communication (with someone) by telephone):

call, phone, telephone, call up