The title means "[Great] Lady," with the word being the feminine counterpart to gəḇir (גְּבִיר) 'virile man, lord, hero.'
Although not present in the Masoretic Text, the plural form gəḇiroṯ (גְּבִירוֹת) is commonly used by academics to avoid the intra-word switching of "gebirahs".
The only time a woman held higher office was in the case of Athaliah, who usurped the throne of Judah.
To further complicate matters, the word gəḇereṯ (גְּבֶרֶת; also גְּבִרְת gəḇirət and גְבָרֶת gəḇāreṯ, meaning 'lady', 'mistress', or 'queen') occurs nine times in the Masoretic Text.
Scholars generally take one of two stances with gəḇereṯ: either classing it as an acceptable variation of the word gəḇirā within the ketiv (featuring a common qere), or opting for a distinct separation of the two words, despite their converged meanings.