cŏ-ŏpĕrātor, ōris, m.,
a joint-laborer, co-operator (eccl. Lat.), Hier. Ep. 143, 1; Aug. Civ. Dei, 16, 5 fin. ; Vulg. Phil. 2, 25; id. 3 Joan. 8.
·noun One who labors jointly with others to promote the same end. ...
Webster's Dictionary of the English Language