A form of scaphe dial, namely a dial with a hollowed-out surface. The term can be applied to a chalice dial, but it more often refers to dials with hour lines engraved in a shallow circular depression in a horizontal metal or ivory plate; in this type of cup sundial the gnomon is usually a short vertical pin. The cup dial often indicates Italian or Babylonian hours; these two indications may occasionally appear on diptych dial as accessories to the main horizontal or vertical dial showing equal hours.