Here’s a little trivia. The Old Testament only uses the feminine form of melek, ‘king’, only once in connection with Israel - and even then, in a poetical passage and in the plural form (Song of Songs 6:8). More often, the word ‘queen’ is used for foreign queens: the queen of Sheba, Vashti and Esther.
I’d like to segue from that to the topic of the g’bîrāh (sometimes also rendered as gebirah), an official rank in the southern kingdom of Judah. In ordinary speech the word meant ‘mistress’ (as opposed to servant), and is used as a feminine equivalent of 'adon ‘lord’ (the feminine form of 'adon is not used in Hebrew). It is never applied to the king’s wife (though the Pharaoh’s wife is called g’bîrāh in 1 Kings 11:19); rather, it is applied to the king’s mother, or in the case of King Asa (1 Kings 15:13; 2 Chronicles 15:16), his grandmother. Fr. Roland de Vaux, in his book Ancient Israel: Its Life and Institutions (p. 117), suggested that the title in this context might be rendered as ‘Great Lady’.
The g’bîrāh had an official position in the kingdom, and so the Books of Kings nearly always mention the king’s mother in the introduction of each reign in Judah (the reigns of Joram and Ahaz - where no woman is named - and Asa - where his grandmother is named - being the exceptions). The title implied a certain dignity and special powers: Bathsheba, the first g’bîrāh, was seated by Solomon in his right hand, the place of honor (1 Kings 2:19). The g’bîrāh’s powers did not simply stem from the influence of a mother over her son as in Bathsheba’s case; it was much more extensive. Asa’s g’bîrāh, his grandmother Maacah, was ousted from her position precisely for abusing this power (1 Kings 15:13). The great authority the g’bîrāh enjoyed explains why Athaliah could easily seize power in the wake of Ahaziah’s death (2 Kings 11:1f.).
It would seem that the ‘Great Lady’ was accorded her rank on the accession of her son. This might explain the career of Hamutal, daughter of Jeremiah of Libnah and wife of king Josiah, who became g’bîrāh in under her son Jehoahaz (2 Kings 23:31), was set aside under Jehoiakim (23:36 - son of Zebidah daughter of Pedaiah) and Jehoiachin/Jeconiah (24:8 - son of Nehushta daughter of Elnathan), and returned under Zedekiah Jehoahaz’s brother (24:18). It’s also possible that the mother became g’bîrāh as soon as her son was designated heir to the throne (as is suggested by 2 Chronicles 11:21-22).
It would also seem that the g’bîrāh could keep her position even after her son’s death: Maacah served as g’bîrāh for her grandson Asa after the very short reign of her son Abijah. Maacah’s case also shows us that the g’bîrāh could be deposed: she was dismissed by Asa because Maacah had favored the cult of Asherah.
There is a close parallel in this with the Hittite position of tavannana, the mother of the heir-apparent who was the lawful queen and who played an important role in government policy and religion. If she survived the king, she retained the position during her son’s reign (or sons, if two brothers survived the throne) - only when the tavannana died did the position pass on to her daughter-in-law, the wife of the incumbent king. There are also possible equivalents in Ugarit (where the queen mother is called 'adath - the feminine of 'adon and therefore the equivalent of g’bîrāh), in Akkad, and less clearly, in Assyria.
As for the northern kingdom of Israel, we have no evidence of a position equivalent to that of the Judahite ‘Great Lady’. The mother’s name is never given in the introductions to the reigns of Israel; and the institution presupposes a dynastic stability usually not found in the northern kingdom. (2 Kings 10:13 does mention a g’bîrāh who can only be Jezebel, but the word is put into the mouth of Judahite princes.)