Is there a Greek verb that means "to eat breakfast" like "desayunar" in Spanish, for example?
Different Determiners change the meaning: Use of the overt Indefinite Article, Definite Article, Partitive, or the Covert □ Article Determiner changes meaning so use the Determiner to convey the desired meaning:
I eat □ breakfast • □ Covert Determiner • [ possibly a general statement - Yes / No: Do you eat □ breakfast? ]
I eat a breakfast • [ some unspecified, Indefinite breakfast meal ]
I eat some breakfast • [ Partitive, partial, possibly a fraction, one, two, a few of many items, or an incomplete breakfast ]
I eat the breakfast • [ some specific, Definite, Defined breakfast meal ]