epiousios

What it means

Epiousios shows up only twice in the whole of Greek scripture, both times in the same line of the Lord's Prayer. That scarcity is the whole problem. Outside the Gospels, the word barely exists in surviving Greek at all, so there is no wide field of ordinary usage to check it against, no shopping list or letter where someone uses it in a way that settles the question. Scholars have argued for over a century about what it's built from: possibly "upon" plus a word for "being" or "existing," suggesting bread for existence or sustenance; possibly "upon" plus a word tied to the coming day, suggesting bread for today or for tomorrow.

So the word covers a genuine range rather than one fixed sense: bread sufficient for staying alive, bread for this present day, or bread for the day just ahead. Each reading changes the prayer slightly, from a request for basic survival to a request timed to a specific sunrise. English has to pick one of those and lose the others.

What English does with it

Most English Bibles settle on "daily bread," following the Vulgate's cotidianum and long liturgical habit, which gives the prayer its familiar rhythm but flattens the ambiguity. Some translators try "bread for today" or "bread for the coming day" to catch the time-sensitive reading. A few footnote "bread for existence" as an alternative. No English word does what epiousios does, because English words for bread don't carry built-in uncertainty about which day is meant.

The common mistake

A famous but unreliable line of argument once claimed epiousios could mean "supernatural" or "of the age to come," based on a scrap of Egyptian papyrus and some early church fathers who read it that way. That reading has mostly been abandoned by careful linguists; the word is far more likely tied to ordinary bread and ordinary days, not a coded reference to heavenly food.