marchioness (n.)

also marquess, c. 1300, marchis, title of nobility, from Old French marchis, marcheis, marquis, etymologically "a prefect of the marches, ruler of a border area," from Old French marche "frontier," from Medieval Latin marca "frontier, frontier territory" (see march (n.1)). Originally the ruler of border territories in various European regions (compare Italian marchese, Spanish marqués, and see margrave); later a mere title of rank, below duke and above earl or count. Related: Marquisate.

Proto-Indo-European root meaning "boundary, border."

It forms all or part of: Cymric; demarcation; Denmark; emarginate; landmark; march (v.) "walk with regular tread;" march (n.2) "boundary;" marchioness; margin; margrave; mark (n.1) "trace, impression;" mark (n.2) "unit of money or weight;" marque; marquee; marquetry; marquis; remark; remarkable.

It is the hypothetical source of/evidence for its existence is provided by: Latin margo "margin;" Avestan mareza- "border;" Old Irish mruig, Irish bruig "borderland," Welsh bro "district;" Old English mearc "boundary, sign, limit, mark," Gothic marka "boundary, frontier."