millstone collar

noun1

1. •
   A ruff; a highly stiffened, pleated, or gathered collar that encircles the neck; popularized during the European Renaissance (mid-16th to mid-17th centuries).

   • There she sits, with her chords and cogitations, which she learned as a child at the French royal court [...] She sits, in a millstone collar, sleeve puffs [...] — 1987