The Mysterious Word Epiusion in the Greek

In the Lord's prayer, we have this clause, give us this day our daily bread. And that's a guess at what Jesus meant because the word he uses for daily in Greek is Epiusias. The early Christian writer origin who was an native Greek speaker commented that nobody was familiar with this word. He speculated that the evangelists coined it when they were writing their Gospels and so exactly what it means is kind of a mystery.