Is it ensure, insure, or assure?
collar (1887), jacket (1881, formerly worn by the younger boys there), etc., from Eton College, public school for boys on the Thames opposite Windsor, founded by Henry VI. The place name is Old English ea "river" (see ea) + tun "farm, settlement."
town (parish), Windsor and Maidenhead unitary authority, historic county of Buckinghamshire, England, across the River Thames from Windsor. It is renowned for Eton College, the largest of the great public (independent) schools of England. Pop. (2001) 4,980.