This is the 35th most frequent Croatian word.
kod
"At," "with," or "near" (indicating location or possession).
Here, 'kod' is used as a preposition to indicate location, meaning 'at' in English, followed by the noun 'kuće' (home) in genitive case.
Kod kuće sam cijeli dan.
I am at home all day.
In this sentence, 'kod' signifies visiting someone, symbolic of going to their place, with 'doktora' referring to 'the doctor' in genitive case.
Idemo kod doktora sutra.
We are going to the doctor's tomorrow.
Here, 'kod' again denotes location, specifying someone's place, with 'prijatelja' meaning 'a friend' in genitive case.