Stephanos of Byzantium - Ethnika
Nikomēdeia: a city of Bithynia, named after Nikomēdēs, son of Zēlas, a most distinguished king. It was also called Olbia. The citizen is Nikomēdeus; and the possessive is Nikomēdeios, with feminine and neuter forms as well. From it Arrian.
Stephanos excerpt (left) is aligned with matched Herodian passages (right). Colors indicate corresponding overlap spans.