This is the 15118th most frequent Russian word.
поликлиникой
"Поликлиникой" (instrumental case) refers to "a polyclinic" — a medical facility offering outpatient services.
The word 'поликлиникой' is used in the instrumental case singular, referring to the clinic specifically in the context of going to or visiting the institution for medical services.
Я вчера ходил в поликлинику за направлением.
Yesterday, I went to the clinic for a referral.
Here, the word 'поликлиникой' is functioning as the subject in the nominative, referring to the clinic's location relative to the narrator's house.
Поликлиника находится недалеко от моего дома.
The clinic is located near my house.
In this sentence, 'поликлиникой' is employed in the instrumental case singular, describing the location where the interaction with the doctor occurred.