What is "pithom"

Pithom also called Per-Atum or Heroöpolis or Heroonopolis ( Greek: or ) was an ancient city of Egypt. Multiple references in ancient Greek, Roman, and biblical sources exist for this city. The exact location of this city remains somewhat uncertain. A number of scholars identified it as the modern archaeological site of Tell-el-Maskhuta. Others say that the site is identified with Tell er-Retabeh, while the 10th century Jewish scholar, Saadia Gaon, identified the place in his Judeo-Arabic translation of the Pentateuch as el-Fayyum, a place located southwest of Cairo.