line_of_defense
1. [ noun ] any organization whose responsibility it is to defend against something
Synonyms: line_of_defence
Examples:

"police are the major line of defense against crime"

Related terms: organization
2. [ noun ] (military) defensive structure consisting of a barrier that can be employed for defense against attack
Synonyms: line_of_defence
Related terms: defensive_structure abattis
Similar spelling:   line_of_defence
  line_of_destiny
  line_of_descent
  line_of_fate
  line_of_duty
  line_of_poetry
  line_of_battle