Wiktionary
back row
n. 1 The last row of seats in a theater or any group of seats. 2 A row near the back of the theater or group of seats. 3 (context rugby English) The row of players in a scrum, consisting of two flankers and a number eight.
Usage examples of "back row".
The professor next noticed, in the back row of the hall, a young man who seemed to be aiming some sort of pistol at him.
A woman once sang from the back row with a very fine contralto voice spoilt by being made artificially nasal.