Genesis 24:16

And the damsel was very fair to look upon, a virgin, neither had any man known her: and she went down to the well, and filled her pitcher, and came up.

Cross-reference

Numbers 31:17 commands killing women who have 'known' a man — the same Hebrew phrasing but in a starkly different, wartime context.

Numbers 31:18 keeps alive girls who have not 'known' a man — sharing the exact virginity language used to describe Rebekah here.