Ethnology is a very modern science, even later than Geology, and as yet hardly known in America, although much cultivated latterly in Germany and France, being considered an indispensable auxiliary to history and geography. ["Atlantic Journal and Friend of Knowledge," Philadelphia, summer 1832]
1650s, "one who regulates" in any sense, agent noun in Latin form from regulate. In English history from 1680s; in American history from 1767, applied to local posses that kept order (or disturbed it) in rural regions. From 1702 as "device for controlling machinery in motion;" the specific sense of "mechanical device or clock used to set the time of other pieces" is from 1758.