symbiosis

implacable

Merriam-Webster's Word of the Day for July 13, 2026 is: implacable • \im-PLAK-uh-bul\  • adjective Someone or something described as implacable is not capable of being appeased or changed. // The project faced implacable resistance from community members, and is now off the table. See the entry > [https://www.merriam-webster.com/dictionary/implacable] Examples: “Unlike, say, the globetrotting stories of Ian Fleming or John le Carré, in which victories only temporarily frustrate an implacable foe, [Agatha] Christie’s smaller worlds feel put right when the cover closes or credits roll.” — The Economist, 17 Jan. 2026 Did you know? Implacable is rooted in the Latin verb placare, meaning “to soothe,” but its im- prefix is a variant of the negating prefix in- (as in inactive) and it signals that there’s nothing warm and fuzzy here. Someone or something described as implacable cannot be soothed, which usually means trouble: implacable is most often attached to words like foe, enemy, hatred and hostility. The opposite of implacable is, of course, placable [https://www.merriam-webster.com/dictionary/placable]; it means “easily soothed,” but sadly isn’t called upon very often. Another placare word is likely more familiar. Placate [https://www.merriam-webster.com/dictionary/placate] means “to soothe or appease”; it’s frequently applied when an angry person is made to feel less so.

fulcrum

Merriam-Webster's Word of the Day for July 12, 2026 is: fulcrum • \FULL-krum\  • noun In technical use, fulcrum refers to the support on which a lever moves when it is used to lift something. In figurative use, fulcrum refers to a person or thing that makes it possible for something to function or develop, or in other words, one who plays an essential role in something. // Although the lead actor was phenomenal, critics suggested that the supporting cast was the real fulcrum of the show. See the entry > [https://www.merriam-webster.com/dictionary/fulcrum] Examples: “The moral fulcrum of Christopher Marlowe’s The Tragical History of the Life and Death of Doctor Faustus, in which a scholar gains knowledge and power through a demonic pact, is a relatively straightforward statement on the human condition.” — Eric Olson, Literary Hub, 14 Jan. 2026 Did you know? The Latin word fulcrum, which refers to the head or back support of a couch, comes from the verb fulcīre, which means “to prop, support.” When fulcrum was first used in English in the 17th century, it referred to the point on which a lever or similar device (such as the oar of a boat) is supported. The literal use easily supported figurative use, and it didn’t take long for the word to develop a meaning referring to one deemed essential to the function or development of something. Despite fulcrum’s multiple senses, the word's meanings have kept a steady theme. In zoology, fulcrum refers to a part of an animal that serves as a hinge or support, such as the joint supporting a bird’s wing.

xeric

Merriam-Webster's Word of the Day for July 11, 2026 is: xeric • \ZEER-ik\  • adjective Xeric means "characterized by, relating to, or requiring only a small amount of moisture." // She is a botanist who primarily studies xeric plants. See the entry > [https://www.merriam-webster.com/dictionary/xeric] Examples: "Thoughtfully designed xeric, or low-water, landscapes can be dynamic, layered and full of color. Native plants and those adapted to the Intermountain West ... provide habitat and food for pollinators and birds while needing a fraction of the water that bluegrass demands." — Pula Davis and Scott Curry, The Colorado Springs Gazette, 16 May 2026 Did you know? Few English words begin with the letter X, but of those that do, a number come from the Greek xēros, meaning "dry." Around the turn of the 20th century, botanists were using the terms xerophyte [https://www.merriam-webster.com/dictionary/xerophyte] and xerophytic [https://www.merriam-webster.com/dictionary/xerophytic] for plants that were well adapted to survive without much water. But when seeking a more generic word that included both animals and plants, they came up, ahem, dry. In a 1926 issue of Ecology, specialists proposed using xeric as a more generalized term for either flora or fauna. They further suggested that xerophytic, among other terms, "be entirely abandoned as useless and misleading." Not everyone liked the idea. In fact, the Ecological Society of America stated that xeric was "not desirable," preferring terms such as arid. Others declared that the word should refer only to habitats, not to organisms. Enough scientists used it anyway, however, that by the 1940s xeric was well documented in scientific literature.

effulgence

Merriam-Webster's Word of the Day for July 10, 2026 is: effulgence • \ih-FULL-junss\  • noun Effulgence means “radiant splendor” or “brilliance.” // Guests oohed and aahed at the sudden effulgence of the pagoda, as the last of its hundreds of candles were finally lit. See the entry > [https://www.merriam-webster.com/dictionary/effulgence] Examples: “No one knows who suggested that the building be lit at night. But the obvious inspiration was Times Square, an area famous for its nighttime effulgence.” — Robert Sharoff, FastCompany.com, 7 July 2025 Did you know? Need a shiny word to bust out at your next disco party, planetarium visit, or fireworks gathering? How about effulgence? It’s not a shiny “new” word, having made its English language debut in the 17th century, but it’s unusual and has a lovely Latin pedigree: the verb fulgēre, meaning “to shine.” Effulgence isn’t used for bog-standard [https://www.merriam-webster.com/dictionary/bog-standard] brightness, however; it’s reserved for shininess that dazzles, inspires, leaves you gobsmacked—in other words, “radiant splendor.”

tacit

Merriam-Webster's Word of the Day for July 9, 2026 is: tacit • \TASS-it\  • adjective Tacit is a formal adjective used to describe something that is expressed or understood without being directly stated. // As roommates, we had a tacit agreement that we would never pry into each other’s affairs. See the entry > [https://www.merriam-webster.com/dictionary/tacit] Examples: “Where modern documentaries are slick productions filled with preconceived notions, embedded narratives, and tacit approval of their subjects, [Frederick] Wiseman’s work is slow, contemplative, and refreshingly slant-free.” — Kevin Slane, Boston.com, 24 Feb. 2026 Did you know? In the first chapter of Emily Brontë’s Wuthering Heights [https://www.britannica.com/topic/Wuthering-Heights], the narrator Mr. Lockwood recounts warily encountering three dogs. Although he was sure to sit still, he admits that “imagining they would scarcely understand tacit insults, I unfortunately indulged in winking and making faces at the trio” (one subsequently leapt onto his knees in fury). His tacit insults were, by the relevant definition of tacit, not expressed with words (instead he used facial expressions). Tacit can also mean “implied or indicated (as by an act or by silence) but not expressed,” as when a tacit agreement is understood without being directly stated, and tacit approval is silently granted. Tacit traces back to the Latin verb tacēre, meaning “to be silent,” which is also the ancestor of the English adjective taciturn [https://www.merriam-webster.com/dictionary/taciturn], used to describe someone who tends to be quiet.