A metaorganism is a highly evolved organism capable of complex thought and interactions.

All animals have clear mutualistic symbiotic interactions with microbes, and can therefore be classed as metaorganisms.

A metaorganism would be classed as at least two or more organisms in an intimate symbiosis, usually for the benefit of all.

A metaorganism would be classed as at least three or more organisms in an intimate symbiosis, usually for the benefit of all.