This is the 849th most frequent Russian word.
ученые
"Scientists."
Here, "учёные" is used as a noun in its plural form, meaning 'scientists', to refer to individuals engaged in scientific research.
Учёные сделали важное открытие.
The scientists made an important discovery.
In this sentence, "учёных" is the genitive plural form of "учёный", indicating possession or relationship, referring to 'scientists'.
Мы должны уважать работу учёных.
We must respect the work of scientists.
This sentence uses "учёная" in its singular feminine form, meaning 'female scientist', to specify a woman performing scientific work.