germ
/d͡ʒɜːm/noun
A tiny living thing, such as a bacterium or virus, that can cause illness.
Example sentence
- “Wash your hands often to avoid spreading germs.”
'The germ of an idea' preserves the older sense of a seed or starting point, which is also behind 'wheat germ' and 'germinate'. The disease sense is informal; science says bacteria or viruses.