This is the 8271st most frequent Russian word.
матвиенко
"Матвиенко" is a Russian surname.
Here, 'Матвиенко' is the last name of a specific individual who is being discussed in the context.
Матвиенко выступила с важной инициативой в Совете Федерации.
Matvienko proposed an important initiative in the Federation Council.
In this sentence, 'Матвиенко' is used to specify the personal surname associated with Valentina, a prominent public figure.
Я изучаю историю работы Валентины Матвиенко.
I am studying the history of Valentina Matvienko's work.
Here, 'Матвиенко' likely refers to either a specific person or a concept associated with this surname, depending on the context of the book.