Pytia (Greek: Πυτιά, Ancient Greek: Πυετία Pyetia also) is curdled milk obtained from an animal's stomach, containing (and used as) rennet.
References Arist.HA522b5, PA676a6, GA739b22, Nic.Al.68, 323. Pytia A Greek-English Lexicon Food in the Ancient World from A to Z How you make the Traditional Pytia by Santorini.gr