I agree, of course, that "sufficient" is a possible translation next to "emeran", "daily", but with St. Theophylact, I believe that th eucharistic meaning cannot be ignored. Where does St. Chrysostom teach about that, in the Homilies on Matthew? I'll re-read that tomorrow.
"Where does St. Chrysostom teach about that, in the Homilies on Matthew?"
Yes, and it is interesting that he gives such an explicitly simple explication about "daily bread" with nary a mention of the Eucharist. Even St. Theophylact, as I pointed out, only mentions it in passing and as an afterthought, and in the commentary on Luke, doesn't mention it at all.
Liddel and Scott traces the etymology in a way that doesn't link this word to "ousia" at all, and also cites Origen's reference to it as being a word that was rare, at best.
I then looked at what St. Augustine has to say. He says that "daily bread" is three-fold: first, asking for what we need physically to live; second, the word of God, divine precepts, hymns, etc...; third, the Eucharist (regarding which he criticizes the Easterners for not receiving it daily, BTW...)