Microbiome 101

The human microbiome wikipedia page:

The human microbiome is the aggregate of all microbiota :that reside on or within human tissues and biofluids along with the corresponding anatomical sites in which :they reside, including the skin, mammary glands, seminal fluid, uterus, ovarian follicles, lung, saliva, :oral mucosa, conjunctiva, biliary tract, and gastrointestinal tract. Types of human microbiota include :bacteria, archaea, fungi, protists and viruses.

That is a very precise and technical definition. But it's not necessary to get