This is the 386th most frequent German word.
groß
"Groß" means "big" or "large" in English.
In this sentence, "groß" is used as an adjective describing the physical size of the house.
Das Haus ist sehr groß.
The house is very large.
Here, "großen" is the accusative masculine singular form of "groß," reflecting the adjective agreement with the noun "Hund."
Mein Bruder hat einen großen Hund.
My brother has a big dog.
In this usage, "große" modifies "Verantwortung," metaphorically indicating significant importance or extent.