bioweaponbi‧o‧weap‧on /ˈbaɪəʊwepən $ ˈbaɪoʊ-/ noun [countable] 
bacteria or viruses (=very small living things that cause illness or disease) used as a weapon to kill a lot of people SYN biological weapon: 
He warned that influenza could be used as a bioweapon.
bacteria or viruses (=very small living things that cause illness or disease) used as a weapon to kill a lot of people SYN biological weapon: He warned that influenza could be used as a bioweapon.