This is the 1734th most frequent Russian word.
городом
"Городом" is the instrumental case of "город" (city), meaning "by/with/as a city" in English.
The word refers to the noun 'city' in the instrumental case, indicating the nature of Moscow in the context of its modernity.
Москва славится своим историческим центром, но также впечатляет как современный город.
Moscow is famous for its historic center, but it also impresses as a modern city.
The word denotes 'city' in the instrumental case, specifying the object admired during the activity of passing by.
Проезжая мимо, мы любовались городом, его архитектурой и огнями.
While passing by, we admired the city, its architecture, and lights.
Here it means 'the city' in the instrumental case, used to express characteristics or state related to the city.