This is the 9302nd most frequent Russian word.
стивен
"Стивен" is a transliteration of the English name "Steven."
In this sentence, 'Стивен' is used as a proper noun to refer to a specific individual, likely a person's name.
Стивен купил новую машину.
Steven bought a new car.
Here, 'Стивеном' is inflected in the instrumental case, showing a grammatical relationship as the subject's interaction with Steven.
Мы поговорили со Стивеном о нашем проекте.
We talked with Steven about our project.
In this context, 'Стивена' is in the genitive case, indicating possession of the subject (the book) by Steven.