Q, quarry, squad, cahier, and quarantine

What links Q, squad, cahier, quarry, and quarantine?

The answer is that these all have etymological links to words for the number four.

The word four itself can be traced back to the Proto-Indo-European word kwetwor. This word evolved into the Old English word feower, which eventually became four as we know it today. Kwetwor also separately evolved into the Latin quattuor from which we get the words for four in Romance languages—e.g. quatre in French.

The character Q—from the James Bond canon—is short for Quartermaster. This word has its roots in the military. A quartermaster was responsible for providing supplies to troops in a particular living quarters. Given that quattuor means four in Latin, it isn’t much of leap to get to a quarter, meaning one-fourth. But how did quarter come to refer to e.g. living quarters and headquarters, in addition to its fractional connotations?

Roman cities—famously arranged around a grid of streets—were frequently divided into quarters by their two main streets that intersected perpendicularly in the centre of town. Initially, quarters referred to these regions—but over time the word lost its link to being specifically a one-fourth part and came to refer to regions, and later, living areas, of any size.

We get the word quarry from the Old French word cuiree, referring to a place where stones are cut into square-shaped pieces. Cuiree is derived from a Latin word itself derived from kwetwor: quadrus, meaning square.

Squad also has similar origins. It comes from the Italian word squadrare, meaning to square off. In the 16th century, the word squadrone was used to describe a group of soldiers who had been arranged in a square formation. The word made it to English as squadron from which were later got squad, which is now used to describe any small group of people.

If you studied French at school, you may recall cahier as the word for exercise book. The word has however also made its way into English. It comes from the Latin word quaterni, which means “four each.” This refers to the practice of folding sheets of paper into quarters to create a booklet.

Finally, quarantine. We’ve heard this word a lot since the start of the COVID-19 pandemic—but have you ever wondered about its etymology? It comes from the Italian quaranta giorni, meaning forty days. During the Black Death in the 14th century, Venetian ships were required to anchor offshore for forty days before they could dock in order to prevent the spread of the disease. From this practice, we get the word “quarantine” which is now used to describe isolation periods of any length.