1. a title given to all members of the House of Lords , including peers and bishops . ( Dukes , although members of the House of Lords, are not addressed as ‘Lord’.) It is also given as a courtesy title to the children of some members of the House of Lords:
Baron Fleming of Rotherham can also be addressed as Lord Fleming.
Lord Derby (= the title of the Earl of Derby)
Lord Doune, the eldest son of the 5th Earl of Murray.
2. a title given to certain high officials:
Lord Lieutenant/Lord Chief Justice/Lord Chancellor.
3. My Lord a way of addressing judges, bishops and peers (except dukes ), showing respect.
➡ note at peerage .