'Queen' once just meant 'woman' — from PIE *gwen, kin to Greek 'gyne' (gynecology). It narrowed to royalty.
The female ruler of an independent state, especially one who inherits the position by right of birth; also, the wife of a king.
From Old English 'cwēn' (woman, wife, queen), from Proto-Germanic *kwēniz (woman, wife), from PIE *gʷḗn (woman). In Old English, 'cwēn' was the everyday word for woman or wife, with no necessary royal connotation. The restriction to 'king's consort' and then 'female sovereign' developed through Middle English as 'cwēn' narrowed socially while 'cwene' covered commoner women. The same PIE root *gʷḗn produced Greek 'gunḗ' (woman) — base of 'gynecology' — Old Irish 'ben' (woman, wife), Armenian 'kin' (woman), and
'Queen' and 'gynecology' are cousins — both from PIE *gʷḗn (woman). The same root that named England's monarch also named the branch of medicine that treats women. And Old English 'cwēn' (woman) split into 'queen' (royal woman) and the archaic 'quean' (a disreputable woman) — the same word diverging into royalty and insult.