τὸν ἄρτον ἡμῶν τὸν ἐπιούσιον δὸς ἡμῖν σήμερον·
Give (to) us our daily bread today.
τὸν ἐπιούσιον (daily) is an adjective that means “the next day” or possibly “necessary”. An early christian writer, Origen, said that this word may have been created by the disciples themselves and was part of everyday speech. It may be idiomatic in nature.
Based on what we know, it could be translated: “Give us our tomorrow’s bread today” or “Give us our next day’s bread today”. That can be interpreted as “give us the future food that we need for existence on a daily basis.” As you can see, this is not a very easy passage to translate, but I think the traditional translation is correct.