noun
(biology) The small mass of cells from which a new organism develops; a seed, bud, spore, or zygote.
A pathogen: a pathogenic microorganism, such as a bacterium or virus.
(figurative) The origin or earliest version of an idea or project.
(mathematics) An equivalence class that includes a specified function defined in an open neighborhood.
verb
To germinate.
(slang) To grow, as if parasitic.