Merriam-Webster's Word of the Day for June 26, 2026 is:

symbiosis • \sim-bee-OH-sis\  • noun

Symbiosis is a formal word that refers to a relationship between two people or groups that work with and depend on each other. In biology, symbiosis refers to the relationship between two different kinds of living things that live together and depend on each other.

// The new playground is the result of symbiosis between multiple stakeholders, including residents, donors, and town officials.

// The bacteria exist in symbiosis with the plant’s roots.

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Examples:

“In the old days, which weren’t that long ago ... there was that ritual moment when a rock ‘n’ roll idol, in the midst of delivering a classic anthem, would point the mic away from himself and into the arena, indicating that it was time for the audience to take over and sing the lines. It might be Springsteen doing ‘Thunder Road,’ or Madonna doing ‘Holiday.’ ... The loving symbiosis of pop star and pop audience doesn’t get much more reverent than that.” — Owen Gleiberman, Variety, 7 May 2026

Did you know?

Symbiosis was adopted by the scientific community in the late 1800s, coming ultimately (via German) from the Greek symbíōsis, meaning “living together, companionship.” Of course, there are a lot of ways to live together and, accordingly, several flavors of symbiosis. When a biological symbiosis between two organisms is mutually beneficial, it is termed mutualism. For example, oxpeckers are birds so named because they “peck” ticks off of infested cattle and wild mammals, a likely satisfying arrangement for both parties, and textbook mutualism. When one organism lives off another at the other’s expense, however (as, for one icky instance, head lice do), it’s called parasitism. If only parents of elementary school students could call upon an equivalent of oxpeckers to engage in mutualistic symbiosis when the need arose, but alas.

Merriam-Webster's Word of the Day for June 25, 2026 is:

jaundiced • \JAWN-dist\  • adjective

Jaundiced means “showing or influenced by feelings of distrust, distaste, or hostility.” Someone described as jaundiced, or as possessing jaundiced opinions or views, is typically understood to feel that way because of negative past experiences.

// She developed a jaundiced view of politics after years of chairing her local school board committee and witnessing all kinds of petty shenanigans.

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Examples:

“Now, I’m not accusing the mayor of anything. I’m saying that all of these actions were highly inappropriate for an elected official. I voted for her, but will forevermore look at her actions with a jaundiced eye.” — Eric Rinehimer, The Retrospect (Collingswood, New Jersey), 23 Jan. 2026

Did you know?

Cast not a jaundiced eye on the word jaundiced—and by that we mean this: don’t dislike or distrust jaundiced because of past experiences with the word or with others like it. Jaundiced is handy for describing the grumps among us who tend toward envy, aversion, or hostility, and who doesn’t know a few of those? This useful 17th century adjective comes from an also-useful 14th century noun jaundice that still refers to a medical condition in which excess bile pigments in the bloodstream and body tissues cause a person’s skin to turn yellow. The connection between the physical condition and the bad attitude lies in the physiological theory of the bodily humors, which holds that a hostile, irritable temperament is caused by excess yellow bile in one’s body.

Merriam-Webster's Word of the Day for June 24, 2026 is:

pantheon • \PAN-thee-ahn\  • noun

Pantheon usually refers to a group of famous or notable people or things. It also refers to the officially recognized gods of a particular people, as well as to the Roman Pantheon, the domed temple begun in 27 B.C. and rebuilt circa 118-128 A.D.

// With her induction into the Rock and Roll Hall of Fame, the distinguished bassist and songwriter joined a pantheon of musical legends.

// His research is primarily dedicated to the Greek and Roman pantheons.

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Examples:

"From cheeky shots of celebrities like Jane Fonda and Arnold Schwarzenegger to extravagant, sensual portfolios of America's Olympic squads, the magazine's pantheon of photographers have helped to define the genre of sports portraiture." — Kahina Sekkaï, Vanity Fair, 14 May 2026

Did you know?

Some of the earliest uses of pantheon in the English language refer to the most famous Pantheon, the circular domed temple built in Rome more than 19 centuries ago (and still standing). We can easily identify the origins of the temple's name, which the Romans borrowed from the Greek word for a temple honoring all their gods. That Greek word, pantheion, combines pan- ("all") and theos ("god"). In today's English, pantheon often refers to all the gods of a particular people (as in "the Egyptian pantheon"), a sense that arose in the 16th century but was rarely used until the 19th century. More often, though, pantheon bears a meaning developed later to refer to the eminent company of the highly venerated, be they human or not. A pantheon of this type includes no deities; it is a group of famous or notable people or things, as in "a book joining the pantheon of great world literature."

Merriam-Webster's Word of the Day for June 23, 2026 is:

quail • \KWAIL\  • verb

To quail is to feel afraid and often to show your fear in a way that can be clearly seen.

// Although giving a 5-minute speech was a requirement for passing the class, a few students quailed at the thought of public speaking, seeming to shrink behind their desks.

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Examples:

“Several came to protest but didn’t want their own voices cited. A woman holding a sign reading ‘I’M A 77 YEAR OLD GRANNY FOR FREEDOM’ quailed at the prospect of having her photo in the newspaper.” — Neil Steinberg, The Chicago Sun-Times, 19 Oct. 2025

Did you know?

Turning to the noun quail, referring to any of a number of chicken-related game birds, for information about the verb quail is of little help. The two are etymologically unrelated, and there’s nothing specific in the behavior of quails to suggest the verb’s meaning. But never fear—the next time you hear quail, think quiver instead. Although quail and quiver are also unrelated, they both start with a distinctive qu and have meanings involving a physical reaction to fear. When you quiver (as in response to, say, hearing things that go bump in the night), you shake or move with a slight trembling motion. Quailing often goes a bit beyond trembling; quail implies shrinking or cowering in fear, as perhaps when the things that go bump in the night suddenly start approaching.

Merriam-Webster's Word of the Day for June 22, 2026 is:

cavalcade • \kav-ul-KAYD\  • noun

Cavalcade most often refers to a series of related things. An older meaning, still in use, is “a procession of riders or carriages”; vehicles or ships in a procession can be referred to as a cavalcade too.

// Since the high-powered console’s debut late last year, video game companies have steadily unveiled a cavalcade of new games that showcase its groundbreaking graphics.

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Examples:

“The event opened with a cavalcade of musicians, dancers and local children, followed by a horse-drawn carriage carrying the Watercress King and Queen ... who threw bags of freshly harvested watercress into the crowd as they paraded up and down Broad Street.” — Paul Coates, The Haslemere (England) Herald, 18 May 2026

Did you know?

Cavalcade is a word with deep equestrian roots: it comes (via French and probably Italian) ultimately from the Latin word caballus, meaning “work horse” or “gelding.” (Spanish speakers may recognize the influence of caballus in the word caballo, meaning “horse.”) In the 17th century, cavalcade was used specifically to refer to a procession of horseback riders or carriages, especially as part of a special occasion, whether joyous or funereal. Over time, that meaning was extended to processions of other modes of travel, including ships, vehicles, or even paraders on foot or float (as invoked by the late singer-songwriter Elliott Smith in his song “Rose Parade” with the lyric “a wink and a wave from the cavalcade”). As a cavalcade of words before and since have done, cavalcade also took on a figurative sense to refer to a series of related things, whether or not they happen to be marching (or trotting) down the road.

Merriam-Webster's Word of the Day for June 21, 2026 is:

assiduous • \uh-SIJ-uh-wus\  • adjective

Assiduous is a formal word that means “showing great care, attention, and effort.”

// Thanks to the assiduous efforts of the local land trust over many years, a substantial amount of whip-poor-will habitat is now protected from development.

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Examples:

“My mom was also assiduous about what we would today call food safety, avoiding anything that could possibly cause illness, especially raw meat: ‘Well done’ was the norm for everything, and anything that could possibly go bad was kept in the fridge.” — James Martin, Work in Progress: Confessions of a Busboy, Dishwasher, Caddy, Usher, Factory Worker, Bank Teller, Corporate Tool, and Priest, 2026

Did you know?

While assiduous means “showing great care, attention, and effort,” and in some situations may be an appropriate substitute for careful, it’s got a bit more oomph than careful in that it suggests a dogged or tireless persistence. If you are assiduous in your efforts (or work, research, analysis, training, preparations, etc.) for example, it’s implied that you’re in it for the long haul, or that you have the ability to “sit with” a task or challenge for a considerable amount of time. This idea is fitting given that assiduous comes from the Latin verb assidēre, meaning “to sit beside.”

Merriam-Webster's Word of the Day for June 20, 2026 is:

longueur • \lawn-GUR\  • noun

Longueur refers to a boring part of something (such as a book or play). It is usually used in the plural form.

// Though not without its longueurs, the opera came to life in the last act.

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Examples:

“Game 3 of the World Series was a stone-cold thriller, with peaks of high drama and longueurs of exquisitely tense tedium ...” — Steve Rushin, The Atlantic, 2 Nov. 2025

Did you know?

You’ve probably come across long, tedious sections of books, plays, or musical works before, but perhaps you didn’t know there was a word for them. The French borrowing longueur has been doing the job for us since the late 18th century. As in English, French longueurs are tedious passages, with longueur itself literally meaning “length.” An early example of longueur used in an English text is from 18th-century writer Horace Walpole, who wrote in a letter, “Boswell’s book is gossiping; ... but there are woeful longueurs, both about his hero and himself.”

Merriam-Webster's Word of the Day for June 19, 2026 is:

indomitable • \in-DAH-muh-tuh-bul\  • adjective

Indomitable is a formal word used to describe something that is impossible to defeat or discourage.

// Juneteenth celebrates the abolition of slavery in the United States, and honors the indomitable spirit of African Americans past and present fighting for justice, liberation, and the fulfillment of this nation’s ideals.

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Examples:

“During his legendary NBA career, Michael Jordan was renowned not only for his athleticism and skill but also for his indomitable will to win.” – Chicago Tribune, 1 Apr. 2026

Did you know?

At five punchy syllables, indomitable is an imposing word, so it’s inevitable that some are perplexed by this synonym for impregnable. But it’s not so tough once you break it into parts. The prefix in- (spelled im- before b, m, and p) means “not” in an innumerable collection of English words. (How many have you counted so far?) The common suffix -able means “capable of, fit for, or worthy of.” Combine those two English affixes with the Latin verb domitare (“to tame”), and voila: indomitable. Indomitable was first used in English as a synonym of wild, describing—appropriately enough—things that cannot be tamed, but over time the wildness associated with indomitable developed into a specific kind of invulnerable strength.

Merriam-Webster's Word of the Day for June 18, 2026 is:

acquiesce • \ak-wee-ESS\  • verb

To acquiesce to something is to accept it, agree with it, or allow it to happen by staying silent or by not arguing. Acquiesce is somewhat formal, and is often used with in or to.

// Eventually, the professor acquiesced to the students’ request to have the seminar’s final class be a potluck lunch.

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Examples:

“It may be just the right time for a chicken burger to become a significant stop on the American burger’s continual evolution—but whether beef-clinging purists will acquiesce to a poultry spin, or cry fowl, remains to be seen.” — Talib Visram, Slate, 6 Apr. 2026

Did you know?

If you’re looking to give your speech a gentle, formal flair, don’t give acquiesce the silent treatment. Essentially meaning “to comply quietly,” acquiesce has as its ultimate source the Latin verb quiēscere, “to be quiet.” (Quiet itself is also a close relation.) Quiēscere can also mean “to repose,” “to fall asleep,” or “to rest,” and when acquiesce arrived in English via French in the early 1600s, it did so with two senses: the familiar “to agree or comply” and the now-obsolete “to rest satisfied.” Herman Melville employed the former in Moby-Dick, when Ahab orders the “confounded” crew to change the Pequod’s course after a storm damages the compasses: “Meanwhile, whatever were his own secret thoughts, Starbuck said nothing, but quietly he issued all requisite orders; while Stubb and Flask—who in some small degree seemed then to be sharing his feelings—likewise unmurmuringly acquiesced.”

Merriam-Webster's Word of the Day for June 17, 2026 is:

wifty • \WIF-tee\  • adjective

Wifty, a synonym of ditzy, describes something or someone eccentrically silly or scatterbrained.

// The play features a wifty character who starts out blissfully unaware of the conflict driving the plot but ultimately pulls it together to save the day.

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Examples:

“When he dreams, he dreams about moving to Wyoming, which he has visited with his family. ... Sometimes when he talks about this, it sounds as ordinary and hard-boiled as a real estate appraisal; other times it can sound fantastical and wifty and achingly naive ...” — Susan Orlean, Joyride: A Memoir, 2025

Did you know?

Whence wifty? Wordsmiths have been wondering for a while. The earliest print evidence of wifty comes from the early 20th century, though the word was certainly being used in spoken English before that. The adjective suffix -y is clear enough; when added to another word it can mean “full of” (as in “muddy), “having the character of” (think “waxy”), “tending or inclined to” (as in “sleepy”), etc. So what’s wift? Well, that element could come from whiff, which as a noun can refer to a quick puff or slight gust of air—a person described by the word wifty might also, if unkindly, be called an airhead. Or perhaps the wift is related to waft, “to move or go lightly on a buoyant medium,” if it’s fair to say that the wifty among us have their heads in the clouds. Whatever once may have been known about it, the answer is now blowing in the wind.