blue line

noun
1
one of the two blue lines that go across the ice between the centre line and the goal line
خط آبی, خط آبی در هاکی روی یخ
2
the players who must prevent the other team from scoring
مدافع, خط دفاعی, بازیکن دفاعی
The two new signings have provided the team's blue line.