This is the 8422nd most frequent Russian word.
надя
"Надя" is a diminutive form of the Russian female name "Надежда" (Nadezhda), which means "hope."
'Надя' is used as a proper noun, referring to a person's name in this sentence.
Надя любит играть на фортепиано.
Nadya loves playing the piano.
Here, 'Надя' is a proper noun, and 'над' is a preposition that combines with 'книгой' to mean 'over the book'.
Надя над книгой была уверена в своих знаниях.
Hovering over the book, Nadya was confident in her knowledge.
'надежду' is derived from the noun 'надежда' (hope) and used here as a direct object in the sentence, demonstrating its connection in meaning.