Bacteria
Etymology
Modern Latin, the plural of "bacterium," from Greek "bakterion" (little staff or rod), a diminutive of "baktron" (staff or cane). The first ones observed under early microscopes were rod-shaped, so they were named for their resemblance to tiny sticks.
noun · /bak-TEER-ee-uh/
Single-celled living microorganisms, some harmful, many harmless or essential.
What it names
Use it for the microscopic living cells all around and inside us — not all of them enemies.
Example
Most of the bacteria in your gut help digest food rather than make you sick.
Related idea
Grammatically, bacteria is plural and bacterium is one — like "data" and "datum." Unlike a virus, a bacterium is a full living cell, which is why we can grow bacteria in a dish but must grow viruses inside host cells.