Linguistic Siblings: 9 Pairs of Words With Surprisingly Shared Etymologies

The words 'galaxy' and 'lactose' have a surprising connection.
The words 'galaxy' and 'lactose' have a surprising connection. / StudioByTheSea/Shutterstock; galaxy illustration by Justin Dodd

Every linguist is familiar with the feeling of delight mixed with vexation when they notice a linguistic connection that had been right under their nose—like that abysmal is the adjective form of abyss. A feeling like that is a testament to the charm of etymology, the study of how words are formed and develop. The connections between words aren’t always as straightforward as the link between run and runner; often, figuring them out requires the subtle unraveling of linguistic evolution, the kind of detective work that makes etymology so utterly fascinating. To illustrate, consider these 10 pairs of words—nine with a deep etymological connection and one pair of false cognates, just to keep things interesting.

1. Disaster and Asteroid

“A pair of star-cross’d lovers take their life,” wrote Shakespeare. You might even call the tragedy of Romeo and Juliet’s love a disaster, which is formed from the Latin words dis, “bad,” and astrum, “star.” We all want to avoid disaster, but who can get out from under a bad star?

Disaster’s sibling, asteroid, is less ominous: It combines star with the Greek -oeidēs, meaning “form,” to describe star-like objects floating in the cosmos. These star-crossed words remind us of the enduring human fascination with the heavens and our attempts to comprehend their influence.

2. Galaxy and Lactose

Scenes From The Atacama Desert - The Driest Place On Earth
The Milky Way appears over the Valle de la Luna in the Atacama Desert. / John Moore/GettyImages

Consider a starlit night far from any city. Above you spreads the grandeur of the galaxy, a swath of creamy luminescence threading its way across the heavens. Now, imagine a cup of coffee with a swirl of slightly sweet milk. These two seemingly disparate entities are linked by more than appearance: They share a common root in the Proto-Indo-European term *g(a)lag-, meaning “milk.” (The asterisk indicates that we have only indirect evidence that the word existed. And, coincidentally, asterisk, meaning “little star,” is also related to disaster and asteroid.)

As you may have guessed, galaxy comes to us from a Latin word for “the Milky Way.” And lactose? French chemist Jean Baptiste André Dumas proposed that name for the natural sugar in milk, using the Latin lac for “milk” plus -ose in analogy to another sugar, glucose. This linguistic connection offers a sweet reminder of our ancestors’ creative imagination, bridging the cosmic and the everyday through language.

3. Company and Pantry

The act of breaking bread together is a universal sign of fellowship and community. The Latin root panis, “bread,” links the words company and pantry. A company was originally just a “companion”—one who shares (com, “together”) bread with you. A pantry, meanwhile, is where bread is stored. Together, these words evoke a sense of community, of shared meals and conversations, and of the nourishment—both literal and metaphorical—that sustains human societies.

4. Sarcasm and Sarcophagus

The sarcophagus of a rich merchant
The 2500-year-old sarcophagus of a rich merchant. / Marc Deville/GettyImages

A biting remark and a stone coffin might seem unrelated, but sarcasm and sarcophagus share an etymological root in the Greek word sark-, meaning “flesh.” Sarcasm, or sarkazein in Ancient Greek, literally means “tear flesh like dogs,” capturing the sharp, biting nature of such remarks. Meanwhile, a sarcophagus is a “flesh-eater,” so named because the limestone used for these coffins was believed to quickly decompose the deceased’s flesh. These words, each macabre in its own way, reveal the darker side of language and its roots.

5. Passion and Passive

Human emotion is a spectrum, and the words passion and passive capture its two extremes. Bound by the Latin root pati, meaning “suffer,” they reflect the spectrum of human experience. Passion is derived from passio (“suffering or enduring”) and has evolved from its very specific meaning in Middle English—“the sufferings of Christ on the Cross”—to represent intense desire or emotion, the active extreme of feeling.

Conversely, passive, from passivus (“capable of suffering or feeling”), encapsulates the quiet acceptance or lack of action, the suffering in silence. Together, these words underscore the richness and complexity of human emotion and resilience.

6. Candid and Candle

A lit candle against a black background
A candle illuminates the darkness. / fhm/Moment/Getty Images

The Latin verb candēre means “shine or glow,” and is the source for both candid and candle. Candēre itself is believed to derive from a Proto-Indo-European *kand-, which also means “shine.” The relationship to candle is obvious. As for candid, it originally meant “white or bright” in Latin but evolved to refer to unvarnished truths, under the idea that we understand things best when they are well illuminated. Just as a candle shines a light in darkness, candid behavior shines a light on the truth.

7. Muscle and Mollusk

You might think the shared m and l link these two words, but it’s actually the diminutive -scus suffix connecting them. Picture the twitch of a muscle under the skin, reminiscent of a mouse moving under a carpet. This visual led to the Latin musculus, meaning “little mouse,” with mūs, of course, meaning “mouse.”  

Mollusk, derived from the Latin molluscus, refers to the soft bodies of creatures in this category. The base mol- comes from the Proto-Indo-European *mel-, “soft,” from which we also get mollify. To this, add the diminutive aspect of the -scus suffix in molluscus. Whether in the flex of an arm or the scuttle of a squid on the ocean floor, these words capture the unexpected interplay of strength and delicacy in the natural world.

8. Navigate and Nausea

Both navigate and nausea trace back to the Proto-Indo-European word *nau-, meaning “boat.” To navigate—derived from the Latin navigare—is to direct a course, originally by ship, harkening back to the image of ancient seafarers plotting their journey across the seas. And what would you endure on such a voyage? Nausea, of course—sea sickness. Though their connotations have broadened over time, both words carry echoes of humankind’s age-old relationship with the sea.

9. Valid andValedictorian

Black graduation cap with gray tassel on yellow background.
Valedictorian means “one who gives a farewell speech during the graduation ceremony.” / DBenitostock/Moment/Getty Images

These two words trace their roots back to the Proto-Indo-European *wal-, meaning “be strong.” Valid is connected through the Latin word validus, meaning “strong.” A valid argument, for example, is one that is logically sound, legally acceptable, or well-founded—concepts that all embody a form of strength.

Valedictorian means “one who gives a farewell speech during the graduation ceremony.” At leave-taking, friends would exhort each other to be strong, so the Latin word vale, from *wal-, took on the meaning “farewell.” Valedictorian, then, is ultimately derived from valedicere, which means “say goodbye,” combining vale with dicere for “say.” This use underlines a sense of strength and accomplishment, marking the end of an academic journey. Thus, both words, though seemingly disparate, echo a sense of potency, resilience, and credibility.

BONUS: Silence and Silhouette

At the intersection of silence and silhouette is a sense of absence—be it of sound or light. The word silence derives from the Latin silere, meaning “be quiet or still.” It represents an absence of sound, a state of tranquility or a lack of disturbance, while silhouette, “an outline or dark shape visible against a lighter background,” represents the absence of light, with all the details hidden in shadow. And what a story it would be if they were etymologically related, but alas! Silhouette is actually named after Étienne de Silhouette, a French finance minister known for his austerity policies. According to one of the theories about this word, getting your silhouette done was much cheaper than having a portrait made, and so the simple, dark representation was named after the miserly minister. While the two words have a suggestive likeness, their actual routes to modern English are, in fact, quite different.

Are you a logophile? Do you want to learn unusual words and old-timey slang to make conversation more interesting, or discover fascinating tidbits about the origins of everyday phrases? Then get our new book, The Curious Compendium of Wonderful Words: A Miscellany of Obscure Terms, Bizarre Phrases, & Surprising Etymologies, out now! You can pick up your copy on Amazon, Barnes & Noble, Books-A-Million, or