Word: light Part of Speech: noun Etymology: Etymology tree Proto-Indo-European *lewk-der. Proto-Germanic *leuhtaz Proto-West Germanic *leuht Old English lēoht Middle English light English light From Middle English light, liht, leoht, from Old English lēoht, from Proto-West Germanic *leuht, from Proto-Germanic *leuhtą, from Proto-Indo-European *lewktom, from the root *lewk- (“to shine”). Cognates * Scots licht (“light”) * Saterland Frisian Ljoacht, Lucht (“light”) * West Frisian ljocht (“light”) * Dutch licht (“light”) * German Licht (“light”) * German Low German Licht (“light”) * Limburgish Leech, Leet, Léït (“light”) * Luxembourgish Liicht (“light”) * Vilamovian łicht (“light”) * Yiddish ליכט (likht, “light”) * Danish and Norwegian Bokmål lys (“light”) * Elfdalian liuos (“light”) * Faroese and Icelandic ljós (“light”) * Norwegian Nynorsk ljos, ljus, lys (“light”) * Swedish ljus (“light”) * Latin lūx (“light”) * Russian луч (luč, “beam of light”) * Armenian լույս (luys, “light”) * Ancient Greek λευκός (leukós, “white”) * Persian رُخش (roxš). Pronunciation: /laɪt/, [laɪt], [lɑjt], [ɫɐɪt], [ləjt] 1. Electromagnetic radiation in the wavelength range visible to the human eye (about 400–750 nanometers): visible light. Labels: uncountable Example: As you can see, this spacious dining-room gets a lot of light in the mornings. Example: Then came a maid with hand-bag and shawls, and after her a tall young lady. She stood for a moment holding her skirt above the grimy steps,[…], and the light of the reflector fell full upon her. 2. Electromagnetic radiation in the wavelength range visible to the human eye or in nearby ranges (infrared or ultraviolet radiation). Labels: broadly, countable, uncountable Example: black light 3. Electromagnetic radiation of any wavelength. Labels: broadly, countable, uncommon, uncountable Example: It’s everywhere. At this moment, as you sit quietly reading this book, you are awash in it. At work, it’s emanating from your electronic devices; step outside for lunch, and the sun bathes you in it. You may receive an extra dose of it when you visit your doctor, pass through security at the airport, or drive through city streets, but minuscule amounts of it are with you always. You cannot see, hear, smell, or feel it, but there is never a single second when it is not flying through your body. Too much of it will kill you, but without it you wouldn’t live a year. “Invisible light” seems like a contradiction. Like Simon and Garfunkel’s “The Sound of Silence,” it’s an oxymoron. We think of light, by definition, as something seen, something that enables our seeing, illuminating the darkness. Unlike dogs, who sniff in order to “get” what an object is, we depend on vision above all our other senses. We rely on light to tell us about our surroundings. But just as there are frequencies of sound audible to other animals that we cannot hear, there is a whole world of light outside our range of vision, a world that is humming with activity. Though we rarely think about this invisible world, our way of life depends on it. It’s because of invisible light that you can do things such as send a text message, use GPS to find your way to a friend’s house, listen to the radio, or microwave a frozen pizza. Invisible light shows us things we would never otherwise see, including our own skeletons and brains and the history of our universe. I was reminded of just how much we rely on invisible light, and how mysterious it remains to us, during a visit from my sister and her family. It was a lazy summer afternoon, and we were sprawled across a few couches sharing a bowl of popcorn. My niece, her shoulders crimson after a day outdoors, was chatting on her cell phone, holding up a promising finger to her mother, who was scolding her for not using sunscreen. My brother-in-law, meanwhile, was asking my opinion on an article he’d read proposing that Wi-Fi be banned in schools because of its dangers. We were all depending on invisible light (for the microwave popcorn, the cell-phone service) while being concerned that it might harm us (sunburn, mysterious Wi-Fi health threats) and confused about what to do to protect ourselves. We need it, and it surrounds us, yet we remain uneasy about living with invisible light, partly because we fear what is unknown. After all, most of us don’t know much about “all the light we cannot see.” This book aims to change that. My hope is to expose the hidden side of the spectrum, to make the invisible (at least temporarily) visible and vivid to you. 4. A source of illumination. Labels: countable Example: Put that light out! Example: And the light ſhineth in darkneſſe, and the darkneſſe compꝛehended it not. 5. A source of illumination. Labels: countable, uncountable Example: We turned off all the lights and went to sleep. Example: The ceiling lights were off, but I knew the narrow light spilling from the lamp on my bureau would be enough for her to see the pale red marks on my chest, which had been fading for so long they had gone back to being shiny again. 6. A source of illumination. Labels: countable, uncountable Example: To get to our house, turn right at the third light. 7. Spiritual or mental illumination; enlightenment, useful information. Labels: countable, figuratively, uncountable Example: Can you throw any light on this problem? Example: He shall never know / That I had any light of this from thee. 8. Facts; pieces of information; ideas, concepts. Labels: archaic, countable, in-plural, uncountable Example: Now these notions are twofold, actions or habits[…], which are durable lights and notions, which we may use when we will. Example: "Well, there's her statement of her case, and according to her lights, it's a just one. She's got a slum-bred mind." 9. A notable person within a specific field or discipline. Labels: countable, uncountable Example: Picasso was one of the leading lights of the cubist movement. Example: Joan of Arc, a light of ancient France 10. The manner in which the light strikes a picture; that part of a picture which represents those objects upon which the light is supposed to fall; the more illuminated part of a landscape or other scene; opposed to shade. Labels: countable, uncountable 11. A point of view, or aspect from which a concept, person or thing is regarded. Labels: countable, uncountable Example: I'm really seeing you in a different light today. Example: Magoon's governorship in Cuba was viewed in a negative light by many Cuban historians for years thereafter. 12. A flame or something used to create fire. Labels: countable, uncountable Example: "There will, I expect, be many such - possibly whole cities in flames - when we consider how many folk may have dropped with lights in their hands." 13. A flame or something used to create fire. Labels: countable, slang, uncountable Example: Hey, buddy, you got a light? 14. A firework made by filling a case with a substance which burns brilliantly with a white or coloured flame. Labels: countable, uncountable Example: a Bengal light 15. A window in architecture, carriage design, or motor car design: either the opening itself or the window pane of glass that fills it, if any. Labels: countable, uncountable Example: This facade has eight south-facing lights. 16. The series of squares reserved for the answer to a crossword clue. Labels: countable, uncountable Example: The average length of a light on a 15×15 grid is 7 or 8. 17. A cross-light in a double acrostic or triple acrostic. Labels: countable, informal, uncountable 18. Open view; a visible state or condition; public observation; publicity. Labels: countable, uncountable Example: The duke yet would have dark deeds darkly answered; he would never bring them to light. 19. The power of perception by vision: eyesight (sightedness; vision). Labels: countable, uncountable Example: My heart panteth, my strength faileth me: as for the light of mine eies, it also is gone from me. 20. The brightness of the eye or eyes. Labels: countable, uncountable Example: He seemed to find his way without his eyes; / For out o'door he went without their helps, / And, to the last, bended their light on me.