This is the 9500th most frequent Russian word.
устименко
"Устименко" is a Russian surname and does not have a specific definitional meaning in English.
In this sentence, 'Устименко' is used as a proper noun, likely a surname for a specific individual.
Устименко всегда помогает своим друзьям.
Ustimenko always helps his friends.
Here, 'Устименко' is again a proper noun, referring to an individual with this surname encountered in the library.
Мы встретились с Устименко в библиотеке вчера.
We met Ustimenko at the library yesterday.
In this usage, 'Устименко' denotes the author of the book who was recognized with an award.