Note:  Do not rely on this information. It is very old.

Lord

Lord (Anglo-Saxon hlaford, "guardian of the loaf," i.e. "master of the house," a word probably of poetical origin) is a title now strictly applicable only to peers of the realm (including the Lords spiritual, or archbishops and bishops who have seats in the House of Lords) and to the holders of certain public offices, such as the Lord Chancellor, Lord-Lieutenant of Ireland, etc. It is also prefixed to the courtesy titles of the eldest sons of dukes, marquises-, and earls, and to the Christian name and surname of the younger sons of dukes and marquises.