In the British system of noble titles, a marquis is a man whose rank sits between duke and earl. The old meaning is “lord of the march”: the march was the border country, the edge of the land, so this was once the man who held that dangerous edge. Today it is simply a high title. Marquis is also the French form of the word, and you will see it in French names. In British peerage writing, marquess is the spelling you will meet more often; marquis feels more French, or more general. The woman’s title is marchioness, not “marquise” in the British system (though French uses marquise). This is not a word for daily life. It lives in history, in formal lists of titles, and in stories about courts and land.