366 Days of Words in Science

232. Kleptoparasitic, adjective. In zoology, describing a behavior in which food, nesting material, or other resources gathered by one animal are stolen by another; also used of species exhibiting such behavior. From Greek kleptes, "thief," + parasitos "one who eats at the table of another." Let's go to the water, you suggest, still half in and half out of your body and wanting to be outside somewhere soft, somewhere sunny. When we get there we find the world is awake and screaming with the joy of winter in the west. Kites, both kinds, in the sky, and bikes, and all manner of dogs and people. Make sure you feel stable,<,/em> a young mother keeps saying to the three dainty girls she is herding down the rocks. Find a place where you feel stable. But before all that, before the end of day, we stop here and inhale, and watch next season's lilacs being made. Does it matter whether generosity is planned or unintended? Some bees forage; some bees filch. Not this one, but some.

231. Onomasiology, noun. A branch of linguistics concerning itself with the ways in which given concepts are named. (Contrasted with semasiology, the study of the ways in which meanings arise from given words.) How does a speaker choose the words they use to express a particular meaning? What terms cluster around an idea? Within a particular language, a thesaurus is an onomasiological dictionary. From Greek onomastos, "named," derived from onoma, "name." After reaching the end of a long line of confusion and troubles, we are greeted by cows. We walk into a lunch fit for a king—or a monk. 240 steps later, we reach this place. Six devas make offerings to the sky: flowers, incense, fruit. Is it peace on their faces? Call it tranquility? Contentment? Equanimity? Your mind fills with synonyms for what you crave.

230. Conurbation, noun. In geography, a level of human settlement made up of several very large, dense metropolitan regions that neighbor each other and have become physically and economically merged over time. For example, the greater Chicago and greater Milwaukee regions–two major urban centers surrounded by suburbs, smaller cities, and towns, linked by roadways and train lines, and whose inhabitants may travel from one to another for work—comprise a conurbation. A term invented by 20th-century Greek architect and urban planner C.A. Doxiadis, best known for having designed the planned city of Islamabad in Pakistan. Doxiadis believed that human settlements (to their own detriment) inevitably tend to become larger and larger in size, and therefore need to be carefully planned and managed in order to maintain their humanity and livability—by, for example, ensuring pedestrian-friendly infrastructure and channelling growth in specific directions so as to avoid sprawl. From Latin con, "with; together," + urbs, "city." I turned off all the lights in the room on the 24th floor. Elbows to carpet, nose to ledge. You clicked the shutter, held your breath, and tried to steal a sliver of that great metropolis. That night I prayed never to wake. But now I look at this and think: I'd like to see what we do next.

229. Formicarium, noun. An enclosure, usually a glass or plexiglass case, in which a colony of ants is housed so that its inhabitants and their architecture can be observed for the purposes of research or recreation. (A form of vivarium.) From Latin formica, "ant." The bristling colony* is gone: gave way to banyan trees, bamboo, chess tables, and moon gates. We close our eyes and try to hear the clamor of the former citadel. All is silence. Sweet potatoes are roasting in a barrel across the street. We'll soon be peeling their steamy skin away. *Today's photo was taken at Kowloon Walled City Park in Hongkong, once the location of a Chinese fort and later an area within the New Territories that was abandoned by both the Chinese and the British during the United Kingdom's 99-year lease of the region. The enclave of about 0.01 square miles, effectively ungoverned, attracted tens of thousands of residents during the Japanese Occupation, the Communist Revolution, and the decades after. Over time, these people—many of them gamblers, drug addicts, gangsters, prostitutes, and other disenfranchised populations—built a compact, crooked shantytown laddered with catwalks, narrow alleys, and self-made infrastructure. By the time of its closure in the late 1980s/early 1990s, Kowloon Walled City had become the single most densely populated settlement in human history. (The image shows a detail from a cross-section drawn by a group of Japanese surveyors who measured every apartment in the city before it was torn down. Read more about Kowloon Walled City here.)

228. Phoresy, noun. In zoology, a method of dispersal or transportation in which one organism is either physically conveyed between two places by clinging to the body of another organism (usually one that is much larger in size), or else spends all or part of its life cycle in such a position. Many mites, for instance, are phoretic on larger arthropods, like beetles or bees. Some blackflies, during their larval stages, have phoretic relationships with small crabs, shrimp, and mayflies. Phoresy is usually—but not always—an association of commensalism, in which the transported animal benefits without harming its steed. From Greek pherein, "to carry." What I want to know is how far a mite dreams of traveling. Does one that crawls upon a louse thinking To Madagascar! feel a sense of disappointment when it finds itself instead amidst the sweaty forest of a toddler's head? But one that couples itself fiercely to a bird, I guess, must thrill at its good fortune—savoring the rush of air and the rise and fall of day and night while on the way from Arctic fields to tropical Hawaii. See also: byssus, obligate.

227. Zero air, noun. In environmental science and meteorology, atmospheric air that has been purified to the point where it contains less than 0.1 parts per million of hydrocarbons: compounds produced by burning fossil fuels that play a critical role in generating photochemical air pollution such as the heavy brown exhalation that hangs over Hong Kong day and night. Zero air is used to calibrate instruments that measure air quality, and is also useful in carrying out gas chromatography, a method of separating and identifying the chemical components of vaporized substances. The substances being sampled can be transported on a jet of this highly purified air, which acts as a silent background, through the gas chromatograph. From Arabic sifr, "zero; nothingness," + Greek aer, "air." You wake up in the darkness and begin the day with a mistake, then keep on going. Get fed, get lost, get pushed into a tram and watch the buildings leaning like they're dying for a crash. Up there you can see the thing that blinds you much more clearly. The veil isn't over your eyes; it's stuffed down your throat. Gods, girl, didn't anyone ever teach you to cough?

226. Figurate, adjective. From Latin figura, "shape, form" (related, to my delight, to the word dough—both have roots in the Proto-Indo European dheigh, "to build"). Of a number, indicating that it can be represented by a geometric shape formed by the arrangement of evenly spaced dots. For example, 6 is a triangular number: * * * * * * 9 is a square number: * * * * * * * * * The forms created by figurate numbers are not limited to two dimensions. 35 is a tetrahedral number; it can be transformed into a three-sided pyramidal shape. Visualizing figurate numbers often gives us an intuitive way of grasping the relationships between numbers; it is easy to see, for instance, that a tetrahedral number consists of stacked layers of triangular numbers. Under a mushroom sky I count the ones I love who live together here. You could strike a clear, high note against the six of them, I think. Each of us is a lone pebble longing after a shape; what makes us stable is the way we are arranged.

225. Vanishing point, noun. From Latin evanescere, "disappear, die away," + punctum, "something pricked; something punctured." In geometry, a point in a two-dimensional image where lines that in reality are parallel (and thus will never meet) seem to converge—so called because as the eye travels along such lines, objects become smaller and smaller in size until they seem to disappear. Though the discovery of vanishing points is most closely associated with Renaissance paintings, ancient Greek and Roman artists were already making use of their illusory qualities centuries earlier. My companions walk ahead while I hang back to look along the corridor, marveling at how small, how pointed I'd appear if I could ever reach the end of it. In truth what seems most natural to the eye is quite impossible. I would give most of what I have to enter this flat world: to become something beautifully punctured.

224. Supertree, noun. In biology, a phylogenetic tree is a visual representation of the evolutionary relationships between organisms over time; it resembles a branching tree. A supertree is created by combining several phylogenetic trees that share some overlapping nodes. Such a structure can be used to represent the web of connections among much larger taxonomic groups, but depending on the technique used to derive it, a supertree may ignore or leave out important primary source data about the character of particular taxa. From Latin superderu, "oak"—which later became the Old English treow, meaning simply "tree," or "wood." Three generations of a single family climbed these wild, constructed giants, reaching for a way to understand the links between them. The wind blew strong against their faces. One wanted to stay up there forever. One wanted to know the truth of the matter.

223. Eudaimonia, noun. From Greek eu, "well; good" + daimon, "spirit; inspiring force; divine being." A word which could be literally translated as "happiness," but which—as articulated by Aristotle in his writings about ethics—really means something more like "the happiness arising from having lived well*." Now used in psychology to refer to a model of wellbeing based not on pleasurable experiences, but the purposeful application of one's strength, commitment, and energy toward some larger goal or meaning. *(Or "living virtuously"—but virtue, in a eudamonic sense, does not necessarily equate to morality. Just as a virtuous knife is one that is sharp, Aristotle argued, or a virtuous shoe is one that cradles and protects the foot on which it is placed, a virtuous human is one whose every behavior is directed toward the fulfillment of his highest and best purpose: whatever that happens to be.) Even if I do nothing else in all the rest of my days, my father says to me, I will be perfectly content with my life just as it is.

222. Deciduous dentition, noun. In medicine, the term for what most of us call "milk teeth" or "baby teeth." From Latin dentitionem, "teething," + decidere, "to fall off; to fall down." Deciduous dentition will have begun to develop by the time an embryo is about six weeks old; after four months in the womb, it will have begun to calcify. After that it takes this set of teeth a little longer—about two years—to emerge into the mouth of the child who bears them, and longer still—another four to ten years—to be replaced by permanent teeth. The word for a species which goes through two sets of dentition in a lifetime is the delicious diphyodont. We have been home for five hours when Sophia erupts up the staircase. Today was her second full day of school, and right now she is plaited and pinafored and shouting my name as if I deserve it. When she smiles, there is a ragged space where two front teeth quite recently were. Right on schedule and way too fast, she's shedding her babyhood. When her arms go around my knees, though, I remember what she looked like the first time I saw her.

221. Amphipathic, adjective. Of a molecule, especially soap and other surfactants, having both hydrophilic (or lipophobic) and hydrophobic (or lipophilic) parts. From Greek amphi, "both; on both sides," and pathikos—normally rendered as "suffering," but also "feeling; experiencing." When algae and other aquatic vegetation decompose, they produce surfactants that normally do little but generate a thick, brownish scum on the water; but a few years ago it became clear that these amphipathic molecules can be a hazard to seabirds. Look, you said, pointing to where the stream from up the hill descended into foam. Do you think there's any way that can be natural? I used to believe that I was harmless. Lately, though, I've seen how these two great and opposite parts have spun into calamity. No one can blame a plant for breaking down according to its nature. Just remember that the breakdown isn't where the story ends.

220. Spicule, noun. Diminutive form of Latin spica, "ear of grain;" related to spina, "thorn." In zoology, any of a variety of tiny structures of similar shape—spicules made of calcium form part of the skeletal structure of sponges, and male nematodes have chitinous copulatory spicules through which sperm passes into females. Astronomers use the word to refer to the hundreds of thousands of intense streams of plasma that are constantly bursting out from the sun and then vanishing, in the process feeding its corona with particles that may serve as the primary source of solar wind. Also, a small, needle-like crystal of ice. When many such spicules are clustered together on a surface, we it call frost. We hike until our feet ache and our armpits sweat, until the air grows blue with late afternoon shade and everything smells like juniper berries and bay leaves. Juniper and bay. The year has taken the shape of a spear; we are driven by its point into the next. Something about this is hopeful, because what else is there now but hope? What's done is done, but what remains undone will matter till the end.

219. Silverskin, noun. The thin, innermost covering that clings to each of the two seeds of a coffee fruit and has, after such seeds have been processed, the texture and feel of crumbling parchment paper. Not strictly a science word—botanists might prefer to call silverskin the remnants of perisperm, a nutrient-rich tissue from which the coffee fruit draws as it develops. When—after having biked a good nine miles to get them home—you roast your first small batch of beans—the last remaining pieces of this once-vital integument fly off. They have turned yellow in the heating, and so float down upon your kitchen counter like so many autumn leaves. It isn't every day you bring a season into being.

218. Sigmoid, adjective/noun. Having a crescent- (or double crescent) shaped appearance, after the form of the eighteenth letter of the Greek alphabet (sigma) as it is written in uncial script: the broad rounded lettering used in European manuscripts between the 4th and 8th centuries. In anatomy, a noun that denotes the final, snaking, portion of the large intestine. And in mathematics, of or referring to a function whose points lie on an S-shape curve when plotted. Two pages of a notebook become filled with hand-drawn boxes, lines, and arcs that I am using to understand one tiny aspect of an unfamiliar world. This undulation, pivoting across the axes of a graph, plays its formal part in turning pixels into airplanes, bicycles, and faces. Later I walk behind one deity after another, watching curving backs. The world is full of many shallow serpents serving curious purposes.

217. Purple Earth hypothesis, the. A theory set forth by University of Maryland researcher Shiladitya DasSarma in 2007 and named for a speculative but imagination-capturing implication to which it leads. The Purple Earth hypothesis proposes that ancient forms of life relied on retinal, a pigment which absorbs green light, to generate energy from the sun. (The sun happens to output most of its energy in the green part of the visible spectrum). When chlorophyll-based organisms eventually appeared, the theory goes, their survival may have depended on a kind of scavenging ability to take advantage of the wavelengths of light left behind by retinal-based life. This, DasSarma believes, is why plant life as we know it evolved to absorb light in the red and blue parts of the spectrum and reflect the green. And since retinal is plummy purple in color, he also argues that large swathes of the early Earth probably appeared to have been covered in a royal blanket. (Salt-loving archaebacteria with retinal bound up in their protein membranes are still around; when these tiny microbes colonize salt lakes, they do lend them their shade.) I want to collect the color of the brightest things—purple cauliflowers, orange beets, a buddha's hand of perfect yellow fingers—and pour them into you again.

216. Platonic solid, noun. A polyhedron (a solid geometric figure whose surface is composed of flat faces and straight lines) meeting the following mathematically elegant criteria: 1) The figure is convex, not concave; it has no indentations. 2) It is regular; its faces are polygons each of which share the same shape and size, are bounded by sides of equal length, and possess interior angles of equal measure. The same number of faces meet, in precisely the same arrangement, at each vertex of the figure. There are only a handful of Platonic solids. They are the 4-faced tetrahedron (or pyramid), the 6-faced hexahedron (or cube), the 8-faced octahedron, the 20-faced icosahedron, and the 12-faced dodecahedron—which I name last, and out of order, because it is the one I love the most. What they share is an extraordinary symmetry: Any one of the vertices, edges, or faces of such a figure can be precisely mapped onto any other vertex, edge, or face, using only the three simplest (Euclidean) geometric transformations. After Plato, who mused that the elements of the universe were composed of such forms, writ small. And from the Greek platon, "broad-shouldered," and Latin solidus, "firm, entire." When I met you, I told you, in all seriousness, that I loved the shape of your head: something so perfect about its form it seemed to have been crafted in some other, higher universe. A Platonic solid, we decided, all in jest. Translate, rotate, reflect all you care to—you are always wholly yourself.