This is the 6562nd most frequent Turkish word.
arka
"Arka" in English means "back" or "rear."
In this sentence, 'arka' is used as an adjective meaning 'back.' It describes the location of the cover.
Kitabın arka kapağını aç.
Open the back cover of the book.
Here, 'arka' again denotes 'back,' referring to the row's position in the sequence.
Arka sıradaki koltuğu seçmek isterim.
I would like to choose the seat in the back row.
In this example, 'arka' is part of the postpositional phrase 'arkasında,' meaning 'behind him,' indicating location relative to a person.