From Longman Dictionary of Contemporary Englishringmasterring‧mas‧ter /ˈrɪŋˌmɑːstə $ -ˌmæstər/ noun [countable] the person who introduces the performers and animals in a circus
Examples from the Corpus
ringmaster• Ben still rolls his eyes and acts the ringmaster in his role as the David Owen of pop.• He was the ringmaster against the former circus act. 