This is the 70th most frequent Bulgarian word.
с
"С" in Bulgarian means "with."
Here, "с" means "with" and indicates that the coffee is combined or served with milk.
Искаш ли кафе с мляко?
Do you want coffee with milk?
Here, "с" indicates the condition or circumstance that affects the speaker's ability to concentrate.
С такава музика не мога да се концентрирам.
With such music, I can't concentrate.
In this sentence, "с" signifies "together with" and shows companionship or association during the action.