roundlet
A small disk, circle or other round object.
[…] let the water continue on the fire a Pater noster while, then take it off, and being cold, put the ſame into ſome roundlet, filling the roundlet brim full.
Where it comes from
From Middle English roundelet, from Middle French rondelet, a diminutive of rondel (“small circle”).
Adapted from the Wiktionary entry roundlet (CC BY-SA 4.0).