I thought it’d be fun to go through some titles and look at the histories behind the words (since I seem to be on an etymology kick lately). We’ll start with royalty and then do the Mr./Mrs./etc. group.
King
It’s a common Germanic word, from the Old English form cyning. Not much beyond that other than that it’s somehow related to kin “race, tribe” (Old English cynn) — so a king was, by extension, a “leader of a tribe.” That connection is dubious but it’s the main theory right now.
Oh, and king is of course related to modern German könig.
Queen
Another Germanic word, seen in Old English as cwen along with a bunch of other forms over the years (cwene, kuen, quyene, qwyn, quewne, queine, and quin being just a few, all from the Middle English period when people exhibited the most creativity in spelling I’ve ever seen).
Cwen came from Proto-Indo-European *gwen- (“woman, wife”), akin to Greek γυνή (“woman, wife”), whence we get words like gynecology and misogyny.
Lord
From the Old English word hláford, which came from hláfweard. That’s a compound word made up of hláf (“load, bread”) and weard (“keeper”, related to our modern warden and, through French, guard). So it basically meant the breadwinner. That meaning extended to mean a master or ruler, and thence to mean God. (But in Old English they usually used Drihten where we would use Lord.)
Sometime during the Middle English period the word simplified from hláford to just lord.
Lady
From the Old English word hlǣfdige, a merger of hláf (“loaf”) and *dīge (“kneader”). The latter isn’t attested elsewhere.
As I was poking around the entries on lady, I found an interesting bit about the word ladybug, by the way. Back in Old English, Hlǣfdige (“Lady”) referred to the Virgin Mary, and its genitive singular form hlæfdigan was often combined with names of other things (plants, etc.) to create “Our Lady’s [plant, etc.]” forms. And thus ladybug means “Our Lady’s bug.” In German they call the ladybug Die Marienkäfer (Mary, obviously), and in the U.K. and elsewhere they refer to it as ladybird.
Duke
From Middle English duc, which is from the Latin word dux (“leader, commander”) via French. Dux comes from duco (“to lead, draw”), and that’s where we get words like deduce, produce, conduct, and seduction (“to draw to oneself”), not to mention educate and the ever-awesome duct tape.
Duchess
From French duchesse, from Latin ducissa (and thence from dux, as with duke, with the feminine -issa ending which we’ll see again in a moment with mistress).
Earl
From the Old English word eorl (“brave man, warrior, leader, chief”). The opposite is ceorl (“churl”), which originally just meant a man without rank.
Baron
From Early Middle English barun, from Old French barun, from late Latin baro, baronem, which originally just meant “man.”
Vizier
From Turkish vezīr, which came from the Arabic word wazīr (وزير, originally “porter,” and from there it came to mean “one who bears the burden of government”). And wazīr came from wazara (وزر, third person singular past tense, “he carried”).
Thanks to Andrew Heiss for the Arabic script here.
It’s fascinating, by the way, how most of these titles evolved from words with comparatively low origins.
Mr.
Shortened form of master and, later, mister. The usual plural is Messrs. (since Mrs. would be confusing to say the least), from French messieurs (plural of monsieur).
Whence master? Latin magister (“master”), with some influence by French words like maître.
Magister comes from the root mag (“great”), where we get the Magna Carta and, also through French (I’m sensing a theme here), Charlemagne. Mag also gives us words like major (“greater”) and majesty.
And of course there’s a Greek equivalent: mag is related to the Greek prefix μεγα-, also meaning “great” or “big,” and that’s where we get words like megabyte and megalomania.
For the heck of it I looked up magic, by the way, and found that it’s from Latin magicus from the Greek μάγος (“member of the Median caste of priests, Magus,” where we get the three Magi). It’s originally from the Old Persian word Maguš, also referring to the Median priests. I think I need to learn more about these priests.
Mrs.
Shortened version of mistress. The plural is Mmes. (from the French mesdames, plural of madame).
Mistress came from master with the -ess suffix (which came from Latin -issa and from Greek -ισσα).
Miss
A shortened version of mistress. When it was first used in the early 1600s, it meant “a kept woman, a concubine.” Towards the end of the 1600s it took on its current, more pleasant meaning, as a title for an unmarried woman or girl.
Ms.
This one didn’t pop up till 1901. As you could have guessed, it’s a merger of Mrs. and Miss as a way to refer to a woman without having to specify her marital status.
Sir
A shortened form of sire, with “the shortening being due to the absence of stress before the following name or appellation.” “Sir Lancelot” rolls off the tongue more easily than “Sire Lancelot,” basically.
Sire comes from Latin senior (“older,” the comparative form of senex, “old”). We also get senile and senator from senex. I’ll let you draw your own conclusions from that.
Ma’am
Shortened from madam, from the Old French madame (ma “my” + dame “lady”, similar to Italian’s madonna and Latin’s mea domina).
Speaking of domina and its masculine form dominus, they come from the root dam, dom, which means “to tame, subdue.” Domain and dominion come from this root.
With that meaning of “tame,” you’d think that domesticate was another grandchild word, but it’s actually from another root, dam, dom (yes, it looks the same), which means “to build.” That’s where we get domicile (via Latin domus “house”).