circlet

noun4

1. •
   A small circle.
2. •
   A ring (typically of gold or silver) worn as an ornament on the head.
3. •
   A crown without arches or a covering.

   • Her faire lockes in rich circlet be enrold. — 1590
4. •
   A round body; an orb.

   • Fairest of stars […] that crown'st the smiling morn / With thy bright circlet. — 1667