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[ hee-lee-uh-trop-ik, -troh-pik ] [ ˌhi li əˈtrɒp ɪk, -ˈtroʊ pɪk ] Show IPA Phonetic Respelling


turning or growing toward the light.

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More about heliotropic

Heliotropic “turning toward the light” is a compound of the forms helio- “sun” and -tropic “turned toward.” Helio- comes from Ancient Greek hḗlios “sun,” which is also the source of the word helium, named for its presence in the chemical composition of the Sun. Meanwhile, -tropic is based on Ancient Greek tropikós “pertaining to a turn,” from trópos “turn.” This same root word is behind English tropical, which we tend to associate today with hot weather and the naming of storms, but the literal sense of tropical describes the zone in which the Sun travels directly overhead in the sky. Heliotropic was first recorded in English in the early 1870s.

how is heliotropic used?

But they have designed [solar panel technology] that they say can be about 30 to 40 percent more effective. They were inspired by the idea that flowers and plants naturally turn to face the sun. They call it, let’s say it’s something called a heliotropic effect, and it’s just because of the direction that the sun strikes and they move.

Cynthia Graber, as quoted in “Clean Energy Contest; and Counting Crickets and Katydids,” Scientific American, September 28, 2009

Most seedling plants are strongly heliotropic, and it is no doubt a great advantage to them in their struggle for life to expose their cotyledons to the light as quickly and as fully as possible, for the sake of obtaining carbon.

Charles Darwin, The Power of Movement in Plants, 1880
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[ uh-prok-suh-meyt ] [ əˈprɒk səˌmeɪt ] Show IPA Phonetic Respelling

verb (used with object)

to estimate.

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More about approximate

Approximate “to estimate” is based on Late Latin approximātus “drawn near to, approached,” which is based on the verb proximāre “to near, approach,” combined with the prefix ad- “to, toward.” Proximāre ultimately comes from the Latin adjective proximus “next,” which is the superlative of prope “near.” Prope is the source of the verb propiāre “to draw near,” which combined with ad- and passed through a couple of sound changes in French, such as -pi- to -ch- because of a phenomenon called palatalization, eventually becoming English approach. Approximate was first recorded in English in the early 15th century.

how is approximate used?

How can we possibly weigh [dinosaurs], and how can we be sure our assumptions aren’t wildly off the mark? Our research, published in Biological Reviews, offers a way to check. We found that two rival ways to estimate dinosaurs’ body size–long thought to be fundamentally at odds–actually offer consistent and complementary ways to approximate the weight of these prehistoric titans.

Nicolas Campione, “How do you weigh a dinosaur? There are two ways, and it turns out they’re both right,” Conversation, September 1, 2020

Researchers have long known that the Babylonians, who lived in what is now Iraq, had considerable mathematical skill: They successfully approximated the square root of 2 and understood the Pythagorean theorem nearly 4,000 years ago—more than a millennium before Pythagoras was born.

Michael Greshko, “Babylonians Tracked Jupiter With Advanced Tools: Trapezoids,” National Geographic, January 28, 2016
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[ key-ret-soo ] [ keɪˈrɛt su ] Show IPA Phonetic Respelling


a loose coalition of business groups.

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More about keiretsu

Keiretsu “a loose coalition of business groups” is a compound of Japanese kei “series” and retsu “line, row.” As with many words in Japanese, both kei and retsu are originally borrowings from Middle Chinese, which exerted substantial influence on other languages in East Asia, from Japanese and Korean in the north to Vietnamese in the south. Kei is cognate with Mandarin , while retsu is cognate with Mandarin liè—though the common origin is clearer if we compare kei and retsu with Cantonese hai and lit. Because Mandarin gradually lost the majority of final consonants present in Middle Chinese, liè ends with a vowel, while Japanese retsu and Cantonese lit preserve the final “tuh” sound that existed in Middle Chinese. Keiretsu was first recorded in English in the late 1970s.

how is keiretsu used?

At dinner parties in Silicon Valley, entrepreneurs brag about having them. At conferences, investors discuss building them. What’s grabbing all the attention? Keiretsu …. The word originated in post-war Japan to describe the powerful groups of intertwined companies that developed as the country rebuilt its economy. The keiretsu replaced the zaibatsu, a system of large, family-held holding companies.

Sarah Tilton, “Keiretsu: An Old Word Brought Back To Life by Today's Internet Gurus,” Wall Street Journal, July 31, 2000

The country’s industrial groups, or keiretsu, are chummy clubs, and banks were willing to quietly bail out a troubled firm with “no questions asked” loans. It was not until the late 1990s that the Japanese government stepped in and began forcing banks to come clean about bad loans.

Eric Weiner, “What the U.S. Can Learn from Japan’s ‘Lost Decade,’” NPR, March 13, 2008
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