 Welcome to the Endless Knot. In this special episode, we're joining team trees to try to plant 20 million trees. And so, since this is all about tree planting, let's see if we can find a family connection between trees and planting via etymology. Tree planting, for the purpose of reforestation, is one of the strategies to mitigate climate change because trees take carbon dioxide, a greenhouse gas, out of the atmosphere, converting it into oxygen and trapping the carbon in the form of biomass. So the idea is to create or recreate forests. The word forest literally means outdoors, coming from Latin forests outside, from the Proto-Indo-European root d'ware, meaning door, also the source of the English word door. It probably came to refer to a bunch of trees from the medieval Latin phrase forestem silvam, the outside woods. Referring to forest outside of the fenced-off woodland that was reserved for royalty, initially in this case Charlemagne. You weren't allowed to hunt in his private woods. That Latin word silva, meaning tree woodland, by the way, probably comes from the Proto-Indo-European root widhu, tree wood, which is also, through the Germanic branch, the source of Old English Wudu and Modern English Wood. The main Latin word for tree, arbor, from which we get arbor day and arboraculture, comes ultimately from the root ered, high, also the source of the words arduous and orthodontist. So unlike wood and silva, the sense development of arbor is figurative. As for the word tree itself, it also comes to refer to trees in a figurative way. Tree from Old English trow comes ultimately from the Proto-Indo-European root deru, meaning to be firm, solid, steadfast. And what is a tree if not firm, solid, and steadfast? And that's why this root led to a number of words having to do with trees or objects made of wood, including trough, a wooden vessel, dryad, a Greek mythological tree nymph, druid, a Celtic religious figure connected with tree worship, and dendrochronology, dating tree rings, which is one way of tracking climate change. But there are also a number of words in English that are connected to the literal meaning of deru, such as trousse, a kind of solid pledge, trust, a solid or firm confidence you might have in someone, and trist, originally meaning a place where one waits trustingly, but now used in the sense of a lover's trist, which ironically might indicate an extramarital affair. But another important word, or really two words now, that we get from this root are truth and trough. In Old English, these were the same word, trough, which had a somewhat broader range of senses. Faith, loyalty, truth, think of Superman's truth justice in the American way. Trough now has the specific sense of a pledge, and is mainly known from the specific contacts of plighting one's trough and betrothal, in other words, an engagement. So a betrothal is a pledge, and this is also etymologically true of an engagement, which comes from old French engagerie, to pledge engage, through the Germanic Frankish language, ultimately from Proto-Indo-European wad, meaning a pledge to pledge, from which we also get the words wed and wedding. Marriage and marry come through old French from Latin maritare, to wed, marry, given marriage, from maritus, married man, husband, which may come from the Proto-Indo-European root mari, young man or young woman. Marriage is also known as wedlock, and the lock part, by the way, is not connected to the word lock, but is instead a suffix denoting an activity from Proto-Indo-European leg to leap tremble, also the source of the word lark, though I would suggest that marriage is more than a lark. And matrimony, which is not related to marry, but instead comes from Latin matrimonium, from the Latin word mater, mother, thus indicating the primary purpose of marriage, for the Romans at least. Now given that producing legitimate offspring has historically been one of the most important aspects of marriage, typically cultures have rules about marrying outside of one's own kin group or other social group, what's called exogamy, to avoid inbreeding, though some cultures have rules about the opposite, endogamy, in which one has to marry within one's social group, such as within one's own ethnic group, caste or religion. Now the degree of closeness in terms of an exogamous marriage differs from culture to culture, and indeed different cultures have different systems of kinship terminology. Not only for this purpose, but also to reflect different social roles relatives are expected to play within the family structure of any given culture. The anthropologist Lewis Henry Morgan identified six distinct patterns of kinship terminologies. For instance, in English-speaking societies there is no distinction between aunts and uncles on the mother side or the father side, and the word cousin is even broader, being applied to any gender, but other cultures have finer distinctions than those, and conversely, other systems use the terms equivalent to brother and sister to include cousins as well. And rules about exogamy can cover not only what we might consider close family, but also larger kin groups, clans, and even whole tribes. In some cases, linguistic exogamy is required in which one must marry a speaker of a different language. The word family comes from Latin familia, which included not only the blood relations within a household, but also the slaves, freedmen, and other members of that household. And in fact, the word familia comes from familus, serving serviceable, from the Proto-Indo-European root de, to set put. The word kin is a Germanic word from Old English kyn, which could refer not only to one's family or relatives, but also a whole people, and comes ultimately from the Proto-Indo-European root genna, to give birth, begat, which is also the source of the word genz, which is the Latin word to refer to one's blood relations, though only through the male line. As for tribe, it comes from Latin tribus, which originally referred to the original three tribes of Rome, the tites, the romnes, and the lucares, coming ultimately from the same root as the word three, Proto-Indo-European tray tree, plus the root of the verb to be, beua, though a connection with the root treb, dwelling, has also been suggested. Related to the word tribus is tribunus, originally the head of a tribe, from which we get the word tribune, and tribura, to give out amongst the tribes, from which we get the words contribute, distribute, retribution, and tribute. And finally, the word clan comes unsurprisingly from Gaelic. Scott's Gaelic clan originally meant offspring, coming to refer in the Highlands to a tribe holding land in common under the leadership of a chieftain. Now the Gaudelic branch of Celtic had no initial puh sound, so what was originally a puh became Gaelic cuh, in the word clan. This word was a borrowing from Latin planta, in the sense of an offshoot, from which of course we get the word plant, and indeed the word plant in non-Gaudelic Middle Welsh means children. Latin planta means sprout, shoot, twig, graft, but also the sole of the foot, because when planting you press down with the sole of your foot. Planta comes from Proto-Indo-European plat to spread, also the source of the word flat, ultimately from the root pella, flat to spread. Also the source of the word planet, through Greek planesthy, to wander, because the planets were the esteris planetae, the wandering stars. So since we have only one planet to live on, we better put our foot down and act as one true global family and make a pledge to plant some trees. If you'd like to donate, head over to teamtrees.org where $1 plants one tree. Think of your family trees. If you've enjoyed these etymological explorations and cultural connections, please subscribe and click the little bell to be notified of every new episode. And check out our Patreon where you can make a contribution to help me make more videos. I'm at alliterative on Twitter and you can visit our website alliterative.net for more language and connections in the podcast, blog, and more.