catoptromancy
Divination by use of mirrors, or other reflective surfaces.
uncountable
Catoptromancy was a species of divination performed by the aid of a mirror. This..was common among the Achaians.
Where it comes from
From the Ancient Greek κάτοπτρον (kátoptron, “mirror”) + -mancy.
Adapted from the Wiktionary entry catoptromancy (CC BY-SA 4.0).