In a Word: Adolescents, Adults, and Adultery

How closely are “adult” and “adultery” related?


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Senior managing editor and logophile Andy Hollandbeck reveals the sometimes surprising roots of common English words and phrases. Remember: Etymology tells us where a word comes from, but not what it means today.

If you rob someone, that’s robbery; and if you bribe someone, that’s bribery. Further, you can refer to your collection of shrubs as your shrubbery and all the machines in your workspace as your machinery. But adultery doesn’t mean being an adult at someone, nor is it a collection of your favorite grown-ups.

In fact, adultery isn’t as closely related to adult as it looks. In fact, adult is more related — both in concept and in etymology — to adolescent, though they don’t look like they have as much in common. So let’s take them apart.

Let’s start with adolescence: At the heart of this word is the Latin root alescere “to grow.” To this was added the prefix ad- “to, at” and we arrive at the Latin verb adolescere, meaning “to grow up.” The present participle of adolescere is adolescens, which gave use the word adolescent.

Don’t remember your grade school grammar vocabulary? A participle is a word that has the characteristics of both a verb (in that it changes tense) and an adjective (in that it’s used as a descriptor). For example, to finish (verb) a project, you’ll put on the finishing (present participle) touches. Or after you type (verb) a document, you have a typed (past participle) essay.

Now here’s the unexpected part: The past participle of adolescere is adultus, the source of our word adult.

Both of these words adolescent and adult eventually became nouns in English, but their meaning is laid bare when you think of them as participles: An adolescent is a “growing-up” person, and an adult is a “grown-up” person.

Is there something about being a grown-up that links to adultery? Etymologically, no. Even though it looks like adult is at the root of adultery, the only part they have in common is the Latin prefix ad-. The rest of adultery traces to the Latin adjective alter “different, other” (also the source of the English alter). Strictly speaking, after tacking on the ad- prefix, the resulting verb, adulterare, should have simply meant “to change,” but it took on more of the sense of “to alter injuriously, to pollute” (like another descendant, adulterate) and eventually to the extramarital monkey business that we know today.

Adulterare (and its noun form adulterium) became the French avoutrie. The English adoption of that word might have kept more closely to that form were it not for Latin-loving scholars during the 15th century who corrected the spelling to adultery to more closely align with the original Latin.

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