This is the 633rd most frequent Lithuanian word.
saulius
The Lithuanian word "Saulius" is a male given name, equivalent to "Saul" in English.
Saulių is the same name, used in the accusative case because it is the direct object of the sentence.
Saulių pažinojau mokykloje.
I knew Saulius in school.
Saulius is used as a proper noun, serving as the name of a person.
Saulius yra mano draugas.
Saulius is my friend.
Saulių is again in the accusative case here, as it indicates the entity about whom good things are heard.