(in some British schools) an older student with some authority over younger students and some other responsibilities and advantages （某些英国学校中负责维持纪律等的）学长 - (also Prefect)
an officer responsible for an area of local government in some countries, for example France, Italy and Japan （法、意、日等国家的）地方行政长官；省长；县长
Word Originlate Middle English (in sense (2)): from Old French, from Latin praefectus, past participle of praeficere ‘set in authority over’, from prae ‘before’ + facere ‘make’. Sense (1) dates from the early 19th cent.