Gnotobiotics is a term used to describe the study of germ-free organisms, especially animals. The term can be broken down into two parts: "gnos-", which means "known," and "-biosis," which refers to living. Other synonyms for gnotobiotics might include terms like germ-free, axenic, or antibiotic-free. These words all describe the concept of an environment that is free from microorganisms, including bacteria, viruses, and other types of germs. Other related terms might include aseptic, sterile, or sanitized. Each of these words could be used to describe a laboratory setting where researchers work with gnotobiotic animals or other germ-free specimens in order to explore various aspects of biology and medicine.