This is the 3768th most frequent Russian word.
четвертая
"Четвертая" means "fourth" (feminine form).
Ordinal number indicating position.
Моя квартира находится на четвёртом этаже.
My apartment is located on the fourth floor.
Ordinal number relating to division or segments.
Четвёртая часть книги была самой интересной.
The fourth part of the book was the most interesting.
Ordinal number indicating rank or position in an ordered list.