Wiktionary
alt. Any defensive measure taken against an attack using bacteria, viruses or toxins n. Any defensive measure taken against an attack using bacteria, viruses or toxins
WordNet
n. procedures involved in taking defensive measures against attacks using biological agents [syn: biological defense, biological defence, biodefence]
Wikipedia
Biodefense refers to measures to restore biosecurity to a group of organisms who are, or may be, subject to biological threats or infectious diseases. Biodefense is frequently discussed in the context of biowar or bioterrorism, and is generally considered a military or emergency response term.
Biodefense applies to two distinct target populations: civilian non-combatant and military combatant (troops in the field). Protection of water supplies and food supplies are often a critical part of biodefense.