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laeotropic

[ lee-uh-trop-ik, -troh-pik ]

adjective

oriented or coiled in a leftward direction, as a left-spiraling snail shell.

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More about laeotropic

The adjective laeotropic “turning leftward” is restricted to describing snail shells. The second element, -tropic “turning (to),” is common enough in the physical sciences, e.g., geography, meteorology, chemistry. The first element laeo- is rare. It comes from the Greek adjective laiós “left, on the left” (there is one ancient lexicographical reference implying the form laiwós). Laiwós is all but identical to Latin laevus and pretty close to Slavic (Polish) lewy. Outside these three branches of the Indo-European languages (and possibly also Lithuanian, among the Baltic languages), laiwo- does not occur. Laeotropic entered English in the 19th century.

how is laeotropic used?

The arms of the cross are slightly oblique; and it is worthy of note that the direction of their inclination is laeotropic, while in Crepidula and Ischnochiton the arms show a slight dexiotropic twist.

Samuel J. Holmes, "The Early Development of Planorbis," Journal of Morphology, Volume XVI, February 1900

… the direction of corresponding cleavages is the same, i.e., the second cleavage is laeotropic and the third dexiotropic, and so on …. Why should this constancy occur?

C. M. Child, "The Significance of the Spiral type of Cleavage and Its Relation to the Process of Differentiation," Biological Lectures from the Marine Biological Laboratory of Woods Holl, 1899
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Word of the day

Perseid

[ pur-see-id ]

noun

Astronomy. any of a shower of meteors appearing in August and radiating from a point in the constellation Perseus.

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More about Perseid

Perseid may have been introduced into English from Italian Perseidi, coined by the distinguished Italian astronomer Giovanni Schiaparelli (1835-1910), who is unfortunately best remembered today for the mistranslation into English of Italian canali “channels” on Mars as “canals,” which has inspired decades and decades of science fiction. Perseid ultimately comes from Greek Perseídēs “offspring or daughters of Perseus,” because the meteors appear to be coming from the constellation Perseus. Perseid entered English in the 19th century.

how is Perseid used?

Comet Swift-Tuttle is the largest object known to repeatedly pass by Earth; its nucleus is about 16 miles (26 kilometers) wide. It last passed nearby Earth during its orbit around the sun in 1992, and the next time will be in 2126. But it won’t be forgotten in the meantime, because Earth passes through the dust and debris it leaves behind every year, creating the annual Perseid meteor shower.

Sarah Lewin, "Perseid Meteor Shower 2018: When, Where & How to See It," Space.com, July 9, 2018

The Perseids also feature “fireballs,” which are meteors of bright color and longer streaks that sometimes have “magnitudes greater than -3.”

Aimée Lutkin, "How to Watch the Perseids Meteor Showers This Season," Lifehacker, July 9, 2018
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Word of the day

decorous

[ dek-er-uhs, dih-kawr-uhs, -kohr- ]

adjective

characterized by dignified propriety in conduct, manners, appearance, character, etc.

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More about decorous

The English adjective decorous ultimately derives from Latin decōrus “acceptable, fitting, proper.” The adjective decōrus is a derivative of the noun decus (inflectional stem decor-) “esteem, honor.” The Latin words derive from the Proto-Indo-European root dek-, dok- “to accept, take,” from which Latin also derives the verb decēre “to be acceptable, be fitting,” whose present participle stem decent- is the source of English decent. From the root dok- Latin forms the verb docēre “to teach (i.e., to make acceptable, make fitting).” The English derivatives of docēre include doctrine and docent. The same root appears in Greek dokeîn “to expect, suppose, imagine, seem, seem good,” and its derivative nouns dógma “what seems good, opinion, belief,” source of English dogma, and dóxa “expectation, opinion, estimation, repute,” and in the Septuagint and the New Testament, “glory, splendor,” which forms the first element in doxology “hymn of praise.” Decorous entered English in the 17th century.

how is decorous used?

If you think British historical dramas are all decorous whisperings about how one should behave upon meeting the queen, this mini-series is here to prove that notion wrong …

Joanna Scutts, "The Very Real Story Behind A Very English Scandal," Slate, July 4, 2018

The normally decorous Senate has been rocked by heated confrontations this week as fellow Republicans have traded personal and profane insults over how much loyalty to show President Trump.

Sean Sullivan and Seung Min Kim, "Animosity in the Senate as GOP trades insults over criticism of Trump," Washington Post, June 14, 2018
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