From BiblePortal Wikipedia

Hastings' Dictionary of the New Testament [1]

SIR ( κύριε).—The title is employed as a term of courtesy or reverence in various relationships. It is the salutation of servants (slaves) to their masters (‘Sir, didst thou not sow good seed?’  Matthew 13:27); of a son to a father (‘I go, sir,’  Matthew 21:30); of the priests and Pharisees to Pilate (‘Sir, we remember that that deceiver said,’  Matthew 27:63); of the Greeks to Philip (‘Sir, we would see Jesus,’  John 12:21). In the English versions ‘lord’ (κύριε) is frequently used in the same sense (‘Lord, thou deliveredst unto me live talents,’  Matthew 25:20;  Matthew 25:22;  Matthew 25:24; ‘Lord, let it alone this year also,’  Luke 13:8;  Luke 14:22;  Luke 19:16;  Luke 19:18;  Luke 19:20). It is also a term frequently employed in addressing Jesus, both by disciples and others (‘Lord, if thou wilt thou canst make me clean,’  Matthew 8:2,  John 11:12); so the woman of Samaria says to Jesus, ‘Sir, thou hast nothing to draw with’ ( John 4:11). See art. Lord.

John Reid.

King James Dictionary [2]

SIR, n. sur.

1. A word or respect used in addresses to men, as madam is in addresses to women. It signifies properly lord, corresponding to dominus in Latin, in Spanish, and herr in German. It is used in the singular or plural. Speak on, sir. But sirs, be sudden in the execution. 2. The title of a knight or baronet as Sir Horace Vere. 3. It is used by Shakespeare for man. In the election of a sir so rare. Not in use. 4. In American colleges, the title of a master of arts. 5. It is prefixed to loin, in sirloin as a sirloin of beef. This practice is said to have originated in the knighting of a loin of beef by one of the English kings in a fit of good humor. 6. Formerly the title or a priest.

Webster's Dictionary [3]

(1): ( n.) A title prefixed to the Christian name of a knight or a baronet.

(2): ( n.) A man of social authority and dignity; a lord; a master; a gentleman; - in this sense usually spelled sire.

(3): ( n.) A respectful title, used in addressing a man, without being prefixed to his name; - used especially in speaking to elders or superiors; sometimes, also, used in the way of emphatic formality.

(4): ( n.) An English rendering of the LAtin Dominus, the academical title of a bachelor of arts; - formerly colloquially, and sometimes contemptuously, applied to the clergy.

Morrish Bible Dictionary [4]

In  Genesis 43:20 the word is adon, often translated 'Lord.' In the Acts (except in  Acts 16:30 ) the word is ἀνίρ, 'man,' and is used as a term of respect. In all other places in the N.T. the word is κύριος, commonly translated 'Lord': in these cases the context determines how it should be rendered.

International Standard Bible Encyclopedia [5]

sûr  : In the Old Testament this word in   Genesis 43:20 the King James Version ( 'ādhōn ) is changed in the Revised Version (British and American) into "my lord." In the New Testament the word sometimes represents ἀνήρ , anḗr , as in  Acts 7:26;  Acts 14:15;  Acts 19:25 , etc.; more frequently κύριος , kúrios , "lord," as in  Matthew 13:27;  Matthew 21:30;  Matthew 27:36;  John 4:11 ,  John 4:15 ,  John 4:19 ,  John 4:49 (the Revised Version margin "lord");   John 20:15 . In  Revelation 7:14 , the Revised Version (British and American) renders "my lord."

Cyclopedia of Biblical, Theological and Ecclesiastical Literature [6]

(as the English of dominus) was the title adopted by priests, as "dom" by monks, and in consequence they were commonly called Sir Johns. There were three sirs sir king, sir priest, and sir knight. At the Reformation it was the title of those in orders, but not graduated those who had graduated being known as magisters (masters).