Difference between Queen Regnant and Highness

QUEEN REGNANT vs HIGHNESS: 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

A high degree (of amount or force etc.)
The quality of being high or lofty
The state of being high
A title of honor given to kings, princes, or other persons of rank.
The state of being high; elevation; loftiness.
A title of honor given to princes of the blood; also, in some German states, a title given to the reigning dukes or grand dukes and their heirs apparent: used with a possessive pronoun, his, her, your: as, his royal highness; her imperial highness.
The state of being high, in any of the senses of that word.
Used with His, Her, or Your as a title and form of address for a prince or princess.
The quality or condition of being high.
(Your Highness or His Highness of Her Highness) title used to address a royal person
The condition of being high or lofty

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

Greatness, Serene, Grandeur, Deign, Grace, Sir, Princess, Queen, Hrh, Royal, Lordship, Prince, Majesty, Excellency, Loftiness

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

Crown, Celestial, Greatness, Serene, Grandeur, Deign, Grace, Sir, Princess, Queen, Royal, Lordship, Prince, Majesty, Excellency

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.

Her royal highness travelled in an English landaulet.
Abbreviation to Imperial Highness is common and accepted.
Her Royal Highness would love to do both!
Your highness, Hooded Robin can imitate any voice!
When his Highness was a little recovered, Mr.
His Serene Highness has agreedto the proposed solution.
Her Royal Highness the Duchess of Gloucester, attended by Lady Caroline Legge, Lady of the Bedchamber to her Royal Highness.
Royal Highness the Duke of Edinburgh shall henceforth be known as His Royal Highness The Prince Philip, Duke of Edinburgh.
Earlier yesterday, His Highness the Amir received at Seif Palace His Highness the Crown Prince Sheikh Nawaf Al-Ahmad Al-Jaber Al-Sabah.
Why is Hereditary Princess Sophie styled as a Royal Highness when the rest of the family are Serene Highness?