Thanks Bhante Dhammanando for the thoughtful interpretation..
The reason I took Ekabhattika to mean one-meal was two-fold. One was as you point out because of the literal meaning, and the other was that I found suttas where Arahants just have one meal for the day.
The Ratthapala Sutta (MN 82) really clarifies this:
"Just then a slavewoman belonging to one of his relatives was about to throw away some day-old porridge. So Ven. Ratthapala said to her, "Sister, if that is to be thrown away, pour it here into my bowl." While she was pouring the day-old porridge into this bowl, she recognized his hands, feet, & voice. So she went to his mother and said, "May it please you to know, my lady, that master-son Ratthapala has arrived."
"Hey, if what you say is true, I give you your freedom!"
Then Ven. Ratthapala's mother went to his father and said, "May it please you to know, householder, that they say the clansman Ratthapala has arrived."
Now at that time Ven. Ratthapala was sitting by a wall, eating the day-old porridge. His father went to him and said, "Ratthapala, my dear, isn't there — What? You're eating day-old porridge? Don't you have your own home to go to?"
"How could we have a home, householder? We have gone forth from the household life into homelessness. We are homeless, householder. We went to your house, but — instead of receiving a gift or a polite refusal — we got nothing but abuse."
"Come, dear Ratthapala. Let's go home."
"Enough, householder. My meal for today is finished
.""http://www.accesstoinsight.org/tipitaka ... .than.html
in Pali: “Alaṃ, gahapati, kataṃ me ajja bhattakiccaṃ”
In this case Ven. Ratthapala refuses more food because he has finished his meal for the day. I think this clearly shows the intention when the eight precepts state that Arahants were ekabhattika (one-mealers). This doesn't mean that it was the one-sessioner's practice because after going on alms round they might not get enough for the day - in which case as I understand it (from the Vinaya) it's ok to eat again to quell hunger (within the allowable time).
So as I see it, Ekabhattika is when you have just one complete meal in the allowable time (not necessarily in one sit). Ekāsanika is when you only eat during one sit.
Dhammanando wrote:I think you've been misled by a translation of ekabhattika that is faithful to the wording (eka = one, bhatta = meal) but not to the meaning, for it conflates ekabhattika with ekaasanika.
Ekabhattika: "one-mealer" means eating only during one part of the day (from dawn to midday), but despite the wording it doesn't actually set any limit on how many meals are consumed during this period.
Ekaasanika: "one-session-eater" means eating just one meal a day.
And so all ekaasanikas are ekabhattikas, but not every ekabhattika is an ekaasanika. Ekaasanika is an optional dhutanga observance undertaken (chiefly) by the gluttonous, while ekabhattika is what the sixth precept entails and what arahants practise.