This is the 3594th most frequent Russian word.
собаку
The word "собаку" is the accusative singular form of "собака," meaning "dog" in English.
Here, 'собаку' is in the accusative case, indicating it is the direct object of the action 'выгуливаю' (to walk).
Я выгуливаю собаку каждый день.
I walk the dog every day.
In this sentence, 'собаку' is used in the accusative case as well, showing that it is the object of the verb 'купил' (bought).
Он купил собаку на рынке.
He bought a dog at the market.
Here, the word 'собака' (nominative case) follows the construction 'У неё есть', which denotes possession.