germ (n.) Look up germ at Dictionary.com
mid-15c., "bud, sprout;" 1640s, "rudiment of a new organism in an existing one," from Middle French germe "germ (of egg); bud, seed, fruit; offering," from Latin germen (genitive germinis) "sprout, bud," perhaps from PIE root *gen- "to beget, bear" (see genus). The older sense is preserved in wheat germ and germ of an idea; sense of "seed of a disease" first recorded 1796 in English; that of "harmful microorganism" dates from 1871. Germ warfare recorded from 1920.