This is the 8396th most frequent Russian word.
муромцева
"Муромцева" is a surname in Russian, typically meaning "of Muromets," referencing the legendary hero Ilya Muromets or the city of Murom.
Here, 'Муромцева' is a proper noun, referring to the surname of a person and is used in the genitive case to denote possession or connection.
Муромцева была известным русским ученым и исследователем.
Muromtseva was a famous Russian scientist and researcher.
In this context, 'Муромцевой' depicts the surname used in the instrumental case, indicating the agent performing an action.
Я прочитал книгу, написанную Муромцевой.
I read a book written by Muromtseva.
'Муромцевой' here is in the genitive case, used idiomatically to reference someone's memory or legacy.