B.w.

(of a motion picture, photograph, drawing, etc.) black and white, as distinguished from color.
a black and white motion picture, photograph, drawing, etc.
warfare that makes use of bacteria, viruses, toxins, etc., to disable or destroy people, domestic animals, and food crops.
abbreviation: b.w.
noun
the use of living organisms or their toxic products to induce death or incapacity in humans and animals and damage to plant crops, etc bw

biological warfare n.
the use of disease-producing microorganisms, toxic biological products, or organic biocides to cause death or injury to humans, animals, or plants.

the use of biological agents as weapons in warfare. also called germ warfare.