Definition of "seigneur"

There was less and less love lost between peasants and seigneurs. The services which the latter had provided for the peasant community in the past had diminished in value.

2002, Colin Jones, The Great Nation, Penguin, published 2003, page 156

Beaumont lives on Sark, a small, autonomous island twenty-five miles off the coast of Normandy, with her husband, Michael, the island's seigneur.

2012 October 29, Lauren Collins, The New Yorker