आचार्य —     प्रिंसिपल —

आचार्य  m) teacher, preceptor; founder or leader (of a school of thought); initiator

प्रधानाचार्य  m) principal, head teacher (director)

प्रधान  m) president, chairman (presidente); a) chief, head, principal, main; dominant

प्रिंसिपल  m) principal (director of a school or college)