Nobly put, sir, nobly put.

I was meaning to ask you about the word "sirrah" which you use not infrequently when engaging in verbal fencing with myself and Rapparee. Whence cameth this delightful word and what is its origion, derivation, and exact meaning (if I may wax a bit redundant)? I'm not saying I haven't heard the word before. I have. But I'd like to get your complete exposition on its cultural history and its salient features, if I may.