blackline

black +‎ line; compare redline, greenline.

blackline (plural blacklines)

1. A document indicating the differences between two versions of another document.
2. (firefighting) A line of deliberately burned material created to stop the advance of a larger fire.
   • 2011, Colorado Outdoors, volumes 49-50, page 11:

     A second squad uses drip torches to begin burning a 15- to 20-foot barrier or “blackline” inside the wetline.

   • 1991, Rangeland Technology Equipment Council Annual Report, USDA Forest Service:

     The helicopter is used to burn blacklines when the relative humidity is above 50%, temperature is below 50 degrees F, and wind speed is less than 6 mph.

blackline (third-person singular simple present blacklines, present participle blacklining, simple past and past participle blacklined)

1. (transitive) To compare versions of (a document) by this method.

• blackline tilefish

• clinkable