The science of Gaia graduates from hypothesis to theory with the recognition that neither life nor its planetary medium is so fundamental that either can be said to control the other. Rather, after four billion years of coevolution, living processes, symbiotic organizations, and the sum of their global niches are all relative to ongoing reformulation by evolving eons of matter, life, and sun. Geobiological history has thoroughly churned them all together into a planetary holobiont that maintains, defends, but also surpasses its parts. Symbiosis is no longer just a biological matter but must now be seen as an ecological principle, an all-pervasive geobiological dynamic.
—Bruce Clarke (2017) in "Planetary Immunity: Biopolitics, Gaia Theory, the Holobiont, and the Systems Counterculture," in Erich Hörl & James Burton, eds. General Ecology: The New Ecological Paradigm. London: Bloomsbury Academic.
Another word for these sympoietic entities is holobionts, or, etymologically, 'entire beings' or ‘safe and sound beings.’ That is decidedly not the same thing as One and Individual. Rather, in polytemporal, polyspatial knottings, holobionts hold together contingently and dynamically, engaging other holobionts in complex patternings.
—Donna Haraway (2016) in Staying with the Trouble: Making Kin in the Chthulucene. Duke University Press.
Therefore, we can scale up examples of endogenous symbioses to ecosystems, biomes and the entire biosphere as holobionts, where the planet holobiont is Gaia. . . . The biosphere is a dynamic system, stabilized via feedback coupling mechanisms so that our entire planet is considered to be one single living being, a supra-organism. By using another term we may say that Gaia, i.e. the biosphere, is the ultimate case of a holobiont.
—Rainer Matyssek & Ulrich Lüttge (2013). "Gaia: The Planet Holobiont." Nova Acta Leopoldina, 111 (391): 325–344.