A female captain or a captain's wife, though the term is archaic and rarely used in modern English.
From captain plus -ess (the feminine suffix). This term emerged when English required gendered versions of titles, though modern usage prefers 'captain' for all genders.
The word 'captainess' reveals how English once required different words for men and women in leadership—similar to 'actress' or 'stewardess'—but modern usage recognizes that leadership titles don't need gendering.
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