Sir said to be the same as Knighthood
Etymology
Sir derives from the honorific title sire; sire developed alongside the word seigneur, also used to refer to a feudal lord. Both derived from the Vulgar Latin senior, sire comes from the nominative case declension senior and seigneur, the accusative case declension seniōrem.The form 'Sir' is first documented in English in 1297, as the title of honour of a knight, and latterly a baronet, being a variant of sire, which was already used in English since at least c. 1205 (after 139 years of Norman rule) as a title placed before a name and denoting knighthood, and to address the (male) Sovereign since c. 1225, with additional general senses of 'father, male parent' is from c. 1250, and 'important elderly man' from 1362.