Many years ago a particular denizen of the metric corner of the internet constantly took me to task about using the word imperial to describe the default set of units employed in the US. I realized that on a pedantic level he was right. The units used in the US are of medieval English origin. The US gallon and bushel were defined in the 10th century, and the inch in the 14th century. The version of English measures last used in the UK are different. They were introduced in the 19th century and are generally called imperial. The imperial gallon and the US gallon are not the same. After a lot of thought, I decided that technically the imperial system is not what is used in the US, and I should not call it imperial.

Others often called our set of non-systematic units USC, for US Customary. I completely did not like this. The use of the word customary was too socially charged for my taste. It was
almost a dog-whistle name for: “if you’re an American then it’s our custom, and if you don’t use this set of units you have no cultural sensitivity.” Worse, some people would call it the US Customary System. The set of measures in the US can in no way be called systematic or a system. It should be USNS, or US Non-System. The United States Code refers to these units as “traditional systems of weights and measures.” I have also used the term skeuomorph units as the US units were originally defined directly, but are now just artifacts that are placed on top of metric measures with no actual purpose. They are simply there to make US measures look comfortably old and familiar. What we use, I’ve also dubbed them US anarchy units (USAU), as they have no rhyme nor reason, and are not a system.

I wanted a different designation. I finally settled on Ye Olde English. Imperial units would be New English units. For me it really showed the archaic nature of the units. The Y was used to replace the symbol used for a thorn, which is a th sound. In actual fact, Ye Olde English would be pronounced The Old English when it was written with a Y. I often shortened this to Olde English units. The designation is meant to be pejorative, but over the years has really lost its psychological impact, and perhaps its usefulness. Pat Naughtin, who is much more measured in his approach, coined the term pre-metric. I’ve tried to use the term pre-metric more often as it conveys the idea that metric is the endpoint, and is not unlike the word prehistoric. It is also non-specific to the US. This tends to drive me back toward Ye Olde English which is more specific to the US.

Andy Weir’s recent book Project Hail Mary pierced my isolated existence in my little corner of the internet, and in life when he wrote sentences like:

“Yes, inches. When I’m stressed out, I revert to imperial units. It’s hard to be an American, okay?”

The word imperial is used throughout Weir’s book to describe Olde English units. I wrote to Andy Weir about metric usage in his book, but I don’t recall making mention of the designation imperial. It just didn’t seem all that big of a deal compared with other more pressing metric questions.

Is the use of imperial to describe Olde English units incorrect? It is well-known that language evolves and changes with usage. The word silly changed from an Old English term for “happy”, to “blessed”, to “pious”, to “innocent”, to “harmless”, to “pitiable”, then “weak”, it then began to mean “feeble in mind, lacking in reason, foolish.” I often see it used as meaning frivolous, or not serious these days. What is definition of “imperial” in the Merriam-Webster dictionary? There are four definitions for imperial as a noun. Number four is most directly pertinent:

4 : belonging to the official British series of weights and measures

Note the word series. The weights and measures of Britain have been redefined throughout the centuries, at least twice in the 19th century, and were finally abandoned (mostly) for
metric weights and measures in the 20th. Part of this series of weights and measures are the group still used in the US to this day. So this dictionary definition encompasses the entire
series of English weights and measures. Of course, those who are interested in sophistry would probably try to argue about the definition of series, trying to restrict it to the last
group and call the last group of measures defined as the true series of measures. I see it as the entire series of English weights and measures.

But how is the definition of imperial determined by lexicographers? Here is how Merriam-Webster discusses the process:

So how does a word get into the dictionary?

A word gets into a dictionary when it is used by many people who all agree that it means the same thing. If your toddler nephew invented a great word that the English language simply can’t do without, don’t write to us to recommend that it be added to the dictionary. Use it. First, you drop the word into your conversation and writing, then others pick it up; the more its use spreads, the more likely it will be noticed by dictionary editors, or lexicographers. If your nephew’s word is one that English speakers decide we need, it has a good chance of getting into the dictionary.

When I look around the US, I see imperial constantly used to describe the English units used here. It is constantly in use, and it appears that even if it was not in the series definition
of imperial, overall usage in the US makes it a dictionary definition. I’m not planning on using it myself, but I’m also not going to wag a finger at others who do.

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If you liked this essay and wish to support the work of The Metric Maven, please visit his Patreon Page and contribute. Also purchase his books about the metric system:

The first book is titled: Our Crumbling Invisible Infrastructure. It is a succinct set of essays  that explain why the absence of the metric system in the US is detrimental to our personal heath and our economy. These essays are separately available for free on my website,  but the book has them all in one place in print. The book may be purchased from Amazon here.

The second book is titled The Dimensions of the Cosmos. It takes the metric prefixes from yotta to Yocto and uses each metric prefix to describe a metric world. The book has a considerable number of color images to compliment the prose. It has been receiving good reviews. I think would be a great reference for US science teachers. It has a considerable number of scientific factoids and anecdotes that I believe would be of considerable educational use. It is available from Amazon here.

The third book is called Death By A Thousand Cuts, A Secret History of the Metric System in The United States. This monograph explains how we have been unable to legally deal with weights and measures in the United States from George Washington, to our current day. This book is also available on Amazon here.