Sir is an English word used to honour a dignified personality. It is derived from the word ‘Sire.’ In majority of the countries, the male teachers are addressed as ‘Sir’ by their students. In England, the famous personalities who are knighted by the queen are also awarded the honorary title of Sir. The female equivalent of Sir is ‘lady’ or ‘Madam.’ Apart from that, those people who are highly ranked in military are also addressed as ‘Sir ‘.