Definition: The word 'Arthrobacter' comes from Greek and means "earthworm" or "worm." It's a genus of bacteria that belongs to the Phylum Archaebacteria and Order Thermotolerant Algeviridae. Definition: 1. Earthworm: This term describes organisms classified under the orders Thermotolerant Algeviridae and Archaeobacteria, commonly known as earthworms. 2. Worm: A type of protozoan, it is a single-celled organism that has an exoskeleton, tubules, and cells in its cytoplasm (the inner layer). Worms are generally anaerobic bacteria that can live on the surface of soil or other surfaces. 3. Earthworm (Arthrobacter) : This genus includes several species which have a wide range of life histories including feeding on soil particles and living as commensal organisms in the human gut. 4. Thermotolerant Algeviridae: These are a large group of bacteria that are able to survive temperature extremes, such as freezing temperatures (-25°C) or extreme heat (up to 130°C). The genus includes soil microorganisms and other non-host organisms that thrive in these environments. In summary, the word "Arthrobacter" refers to a group of earthworm-like bacteria that can live on the surface of soil or other surfaces.