> >> Feachtus tra do Diarmaid mac Cerbaill oc tomailt fheisi na Temrach,
> >> Mugain ingen
> Concraid meic Duach di Eoganacht Chaisil fora laim .i. mathair Aeda
> meic Diarmada.
> Then once Diarmaid (was) eating (at) the feast of Tara, Mugain the
> daughter of Conchrad mac Duach of (the) Caisel Eoganacht at his hand,
> the mother of Aed mac Diarmaid.
> tomailt -- verbal noun of 'do-meil...wearing away, consuming..act of
> consuming food or drink...food...feast
"do·meil" means "to eat, consume" if the object is food, but in the
context of time, events or abstracts it is rather "to spend, use...".
A better translation here would be "once D. was celebrating the Feast