Definitions for bcg vaccine
Random House Webster's College Dictionary
a vaccine made from weakened strains of tubercle bacilli, used to produce immunity against tuberculosis.
Origin of BCG vaccine:
U.S. National Library of Medicine
An active immunizing agent and a viable avirulent attenuated strain of Mycobacterium tuberculosis, var. bovis, which confers immunity to mycobacterial infections. It is used also in immunotherapy of neoplasms due to its stimulation of antibodies and non-specific immunity.