Translation:The breakfast today was better than yesterday.
Technically the translation is wrong. In formal English the sentence is comparing two things which (in this translation) are mentioned as (1) the breakfast today, and (2) yesterday. It is possible to compare today and yesterday, or to compare today's breakfast and yesterday's breakfast, but you cannot, in correct English, compare a day and a meal. It is lazy English and would be marked as an incorrect English sentence by a university English teacher. The correct English should be that the breakfast today was better than yesterday's.
I don't think so, without any clarification it'd probably be understood as 'breakfast'. Πρωινό is mostly used as an adjective (breakfast = πρωινό γεύμα). 'Morning' is mostly πρωί.
I am not saying that your translation is wrong, but I think that since one of the two GR-EN translation matches is strongly favoured, you would need some additional context to move it away from the default translation. In other phrases, like ' Ένα (όμορφο) πρωινό του Οκτώβρη...', it is clear that πρωινό = morning with or without the adjective before it. But the exercise here is too ambiguous that I believe would favour the 'breakfast' translation. (And I realise this is not very well written, sorry.) Edit: I added (όμορφο) before πρωινό του Οκτώβρη, that's the adjective I was referring to.
We also have translations with "today's breakfast" as correct and accepted. Of course, you realize that that means you had something else wrong. But you didn't make a Report. We have no way of knowing what the rest of the sentence said.
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