In biology, inoculum refers to the source material used for inoculation. Inoculum may refer to: In medicine, material that is the source of the inoculation in a vaccine In microbiology, propagules: cells, tissue, or viruses that are used to inoculate a new culture Microbial inoculant, the beneficial introduction of microbes to improve plant health A method of propagation of fungal plant disease transmission Fermentation starter, in food production See also: Fear Inoculum, a 2019 album by American rock band Tool