bacterium science definition
Plural bacteria bacteria Any of a large group of one-celled organisms that lack a cell nucleus, reproduce by fission or by forming spores, and in some cases cause disease. They are the most abundant lifeforms on Earth, and are found in all living things and in all of the Earth's environments. Bacteria usually live off other organisms. Bacteria make up most of the kingdom of prokaryotes (Monera or Prokaryota), with one group (the archaea or archaebacteria) often classified as a separate kingdom. See also
archaeon, prokaryote.Related Forms:
Usage It is important to remember that
bacteria is the plural of
bacterium, and that saying
a bacteria is incorrect. It is correct to say
The soil sample contains millions of bacteria, and
Tetanus is caused by a bacterium.
Learn more about bacterium
Related Articles