backline

Noun

back line (plural back lines)

1. Collectively, the defenders of a team.
   • Battling Bolton disputed the goal, claiming Drogba was offside, but the Ivorian appeared to have timed his angled run across the visitors back line to perfection to race onto a fine Michael Essien pass and ensure Chelsea moved back into fourth place in the Premier League.2010 December 29, Chris Whyatt, “Chelsea 1 - 0 Bolton”, in BBC
2. (field hockey) The line running across the goal to the corners of the playing field.
3. The players known as the backs, whose primary responsibility is defense.
   • A running fullback radically improves the attacking prowess of any back line, particularly if she is able to read a play, knowing when it's time to hit the line at pace or to join the line to act as an extra attacker.2011, Mathew Brown, Patrick Guthrie, Greg Growden, Rugby For Dummies, →ISBN, page 58
4. The imaginary tactical line across the field that passes through the backs, through their primary line of attack/defence (i.e. excluding any players in a more backward defensive position).