noun
1.
a. : a police barrier or line about a burning building — usually used in plural
b. : a line of fire hose
2.
a. : firebreak
b. : a line of hardwood seedlings planted along abandoned railway grades for the protection of young conifers
c. : the gutter or strip dug or scraped in a forest-fire control line
d. : the front line of an advancing prairie or forest fire