[zozbot234]

The article points out that this word is effectively a hapax legomenon in Ancient Greek. It only shows up in this NT context, and not elsewhere. We can speculate about what it means from the surrounding text-- it appears to modify "bread"; its morphology-- it decomposes nicely into "over" + "being, essence"; and its parallels in other sources, but we'll never be sure what it means. It might just as well be a prayer for being sustained in abundance, and this might even be expected since people in the time of Jesus thought that the end times were at hand, and with those the "world to come" where the righteous would be rewarded. But even that is speculation.

[defaulty]

I have heard this phrase (daily bread) compared to the story of God providing manna (something flaky, often compared to flour & bread) for food in Exodus 16. In that story, the Israelites were instructed to only collect the manna for each day. If they tried to keep some for the second day, it would become rotten. This meant they were reliant on God's provision each day.

In the same way, this prayer may be about provision of bread enough for today, of sufficient/satisfactory quantity, no more than we need (per Exodus), just what we need right now. You'd obviously then want to pray this each day, and rely on God's provision daily. So daily isn't a transliteral interpretation but more a descriptive one