Difference between Queen Regnant and Duchess

QUEEN REGNANT vs DUCHESS: NOUN

A female monarch who reigns in her own right, in contrast to a queen consort, who is the wife of a reigning king.
A queen reigning in her own right.
A female sovereign ruler

The female ruler of a duchy (where women can reign).
The female spouse or widow of a duke.
The wife or widow of a duke; also, a lady who has the sovereignty of a duchy in her own right.
A part of ladies' head-dress in the seventeenth century, apparently a knot of ribbon.
A variety of roofing-slate two feet long and one foot wide.
The consort or widow of a duke, or a woman who holds the sovereignty or titles of a duchy.
Used as the title for such a noblewoman.
A woman holding title to a duchy in her own right.
The wife or widow of a duke.
The wife of a duke or a woman holding ducal title in her own right

To court or curry favour for political or business advantage; to flatter obsequiously.

Regious, Kingling, Prince, Queen of england, Queenhood, Kingless, King, Grand duchess, Queen consort, Monarch, Female aristocrat, Queenlike, Queen dowager, Female monarch, Queen

Baroness, Monarch, Courtier, Queen consort, Royal, Empress, Prince consort, Princess, Countess, Jacqueline, Angouleme, Grace, Duchesse, Dowager, Queen

Unqueen, Regious, Kingling, Prince, Queen of england, Queenhood, Kingless, King, Grand duchess, Queen consort, Monarch, Female aristocrat, Queenlike, Queen dowager, Queen

Aristocrat, Nobleman, Viscountess, Monarch, Courtier, Queen consort, Royal, Empress, Prince consort, Princess, Countess, Grace, Duchesse, Dowager, Queen

For example, Urraca, unlike any other woman discussed in this project, ruled as queen regnant, though her right to do so was frequently contested.
Queen Regnant automatically passes on her dynastic name to her son or daughter who succeeds her.
In most countries, Jeanne would automatically have become queen regnant on the death of her baby brother.

KHARY: Have the Duchess follow me as well.
The Duchess swings over and takes a look.
Oh hello, this is the Duchess of York.
The Royal Foundation of the Duke and Duchess of Cambridge and the Duke and Duchess of Sussex, which supports philanthropic activities and program.
Hilary Mantel and the duchess's new clothes I was present for the author's so-called "attack" on the Duchess of Cambridge.
Duke and Duchess of Cambridge, Prince Charles and the Duchess of Cornwall.
The Duchess of Cambridge and the Duchess of Cornwall, in matching blue outfits, travelled by carriage while their husbands rode horseback.
She told staffers that Duchess was a working service dog, but they said that taking Duchess along was inappropriate.
She was a duchess in Prussia by birth and by marriage Duchess of Mecklenburg.
This makes the readers wonder why this Duchess is no longer his present Duchess.