The rh and z in this word are good hints that it has Greek roots, as indeed it does. It came up from Proto-Indo-European *wrad- “branch, root”, appearing in Greek first as ῥίζα rhiza “root” and ῥιζοῦσθαι rhizousthai “to take root” and then ῥίζωμα rhizoma “stem, race, element”. The same PIE root also pushed up sprouts in Latin with radix and in the Germanic languages with words that became (among others) English root and wort. But it also jumped across from Greek to English via Latin, to give us our rhizome and rhizomatic (and rhizomatous).
But why would we need another word for it? Well, there are roots and then there are roots. When we think of roots, we think of a stem that branches and branches and branches underground (as it does aboveground). It’s an easy kind of fractal. It’s the model we use for a great many things. Look at biological history: the various kinds of life form branch apart and apart and apart; at some point, the primates split off, and at another the monkeys split from the apes, and later homo splits from other apes, and Neanderthals split off closer up. In language history, we trace English to West Germanic, which traces back to Proto-Germanic, and that traces back to Proto-Indo-European, as do, from their separate branches, languages such as Italian, Greek, and Russian (but not Finnish or Estonian or Hungarian, which are Finno-Ugric). And in syntax we can split up a sentence into components that draw a nice tree, with each phrase having a possible specifier, a head, and a possible complement, and the complement being another phrase, and so on.
But not all root systems are like that. Some plants have incredibly involved root systems – not even actually roots, botanically speaking, but actually underground stems – that spread horizontally underground and have multiple plants springing up from them (like the ascenders and dots poking up from the word form rhizomatic), all connected together underneath at nodes. If you cut away a part of this system, another plant can spring up from it – and it may even reconnect with the original system. This brings to mind another kind of fractal, one where you may follow a split from a lower level to connect at a higher level, one where everything is downstream and upstream from everything, an infinity of Klein bottles and Möbius strips all connected: the World Wide Web.
But botanics didn’t have the World Wide Web to refer to when different kinds of root (and underground stem) systems were being described, so English (and other languages) just borrowed from Greek, allowing the root to sprout with a different shade of meaning. And, for that matter, the World Wide Web wasn’t around in the 1970s when Gilles Deleuze and Félix Guattari wanted to describe an approach to knowledge that was more interconnected than the standard branching model. So they, too, used rhizome and rhizomatic to describe their vision of multiplicity, with its principles:
* Any point of a rhizome can be connected to anything other, and must be.
* It is only when the multiple is effectively treated as a substantive, “multiplicity,” that it ceases to have any relation to the One as subject or object, natural or spiritual reality, image and world.
* A rhizome may be broken, shattered at a given spot, but it will start up again on one of its old lines, or on new lines.
* A rhizome is not amenable to any structural or generative model. It is a map and not a tracing.
(Extracted from A Thousand Plateaus, translated by Brian Massumi.)
Indeed, even systems that we think of as being standard branching models have rhizomatic characteristics. It is thought that at least some modern humans have Neanderthal DNA from interbreeding. English has borrowed vocabulary massively, and has even borrowed some syntactic structures from other languages, nor is it the only language to do so. (And Finnish is loaded with borrowings from Germanic too.) And our nice, tidy syntax trees turn out to involve lots of movements and involutions and to present difficulty with diagramming neatly even some fairly casual and unexceptional sentences such as we might say on the phone.
In such things as language, the multiplicity of interconnectedness goes well beyond what you get with plants. A word like rhizomatic is almost like a rhizome connecting with a different kind of plant and sending up a hybrid sprout. Consider that rh is not a native English beginning for a word, nor is the sound it represents in the original (a voiceless or aspirated /r/); we keep the spelling (given it by Latin) but change the prununciation. The z is also a sign that a word does not originate in Anglo-Saxon, as in Old English /z/ was just a way s was pronounced in some places (as /v/ was a way f was pronounced in some places) – the letter was borrowed later when we needed it. As to the vowel in between, i, we say it /aɪ/ rather than /i/ (as in pita) because the way we say our “long” vowels changed over time, and when we borrow words we may (but don’t always) say them according to the way our English words have come to be said.
And then there’s the tone the word gets from the matic ending, which adds to its lexicalized meaning with associations and overtones from words such as automatic, with its technological edge, and pragmatic, with its philosophical note, and asthmatic, which may lead us to detect a bit of wheezing in the rh or z. We may get some rhythm from its double trochee. We may hear this root system rise to the attic. We may even rhyme it with try some haddock. A myriad of connections are available, variously strong, and it will sprout up a little differently in each different mind in each different instance.
Thanks to C. Fletcher for asking about rhizomatic.