Adult and Adultery
Published: 2021-12-09In English language, we can observe a myriad of etymological relationships between words. Some connections are clear and straightforward, but for me, most of them are non-trivial and cannot be understood just by looking at the form or meaning. How many people can think of the word “umbrella”, when they learn the word “somber”?1
On the other hand, the opposite can sometimes happen to us (or at least to me). When I first learned the word “adultery”, meaning “sex between a married person and someone who is not that person’s spouse”, I immediately associated it with the word “adult”. That totally makes sense, because it’s usually what adults do, and “adult” is the prefix of “adultery”.
Also, when I came across the word “adulterate”, meaning “to make something impure and poorer in quality, by adding something else”, I thought of “adult” again, and understood it pretty smoothly! I thought that there must be something related to “changing”, and that makes sense too.
But these two assumptions turned out to be wrong. The word “adult” comes from the Latin “adultus” (meaning “grown-up”), which is the perfect participle of “adolēscō” (meaning “I grow up”, cf. adolescent). “Adolēscō” can be further divided into “ad-“ (probably meaning “toward”) and “olēscō” (meaning “I grow”).
“Adultery” and “adulterate”, however, come from the Latin “adulterō” (meaning “I commit adultery” or “I adulterate”), which is the combination of “ad-“ and “alterō”, meaning “I change” (cf. alter). There’s no similarity between the words “olēscō” and “alterō” at all.
Interestingly, the word “adult” has hardly changed in form since the 16th centuty:
1531 T. Elyot Bk. named Gouernour ii. i. sig. Niv Soche persons, beinge nowe adulte, that is to saye, passed theyr childehode.2
But the word “adultery” had so many forms in the past, one of which is “aduoutrye”:
1525 Ld. Berners tr. J. Froissart Cronycles II. xliii. 139 She was but a bastarde, and borne in aduoutrye.3