When Entries Begin With Numbers

Where do you think these index entries should appear in the alphabetical sort order?

  • 1984 (Orwell)
  • 7-Eleven
  • 10 Downing Street
  • 49th Loyal Regiment

Indexers usually turn to style guides to ensure their practices are consistent across the industry. And for the North American publishers, the Chicago Manual of Style (CMOS) is usually the one searched first.

This particular question is addressed in Section 16.65 in CMOS 16th Edition, which states “Isolated entries beginning with numerals are alphabetized as though spelled out.”


  • 1984 (Orwell) will be under the O’s as nineteen-eighty-four
  • 7-Eleven will be under the S’s as seven-eleven
  • 10 Downing Street will be under the T’s as ten downing street.

However, when I indexed Our Quarrel With the Foe: Edmonton’s Soldiers 1914–1918 by Ian Edwards, a different approach was needed. As a military history, it is full of brigades, divisions, battalions, and regiments, and each one begins with a number.

From “1st Canadian Automobile Machine Gun Brigade” to “258th Battalion”, it only made sense to gather these together under “Numbers”. And because the soldiers and their teamwork was the main focus of the book, it seemed important to put the Numbers at the front of the index, instead of at the back. This way, readers will see right away how the index is organized with numbers together.

Here’s what the first few lines of the index looked like.

As with everything to do with indexing, the correct approach is the one that serves the reader best.

Indexable Names vs. Passing Mentions

Occasionally I’m asked the question “Why are these names not mentioned in the index?”

As a rule, all names should be in the index, except when they are passing mentions. The clearest case is when the name is used for illustration.

Here’s an example from the Remarkable Retail by Steven Dennis:

…[T]he stated goal of being the Casper of adult incontinence, the Bonobos of work boots, the Uber for tenured professors,....

On reading this, even if you don’t know what Casper is, you get the point from the context that is about the desire to be a disruptive retailer. And if you looked up Casper in the index and it brought you here, you would be annoyed because there is nothing here that’s actually about Casper. That’s why Casper is not in the index.

This example is from Humankind by Brad Aronson:

Saying yes to others can make all the difference. Besides helping people like Julius and Caloua get a start in life, it can change the world for a homeless teen…

Julius and Caloua are in the index, but there is no entry pointing to this paragraph. Their homeless situation is discussed elsewhere in the book, but there is nothing here about them specifically. Sending the reader here would be like sending them on a wild goose chase.

Now here’s an example where some indexers would omit the name, but I decided to include it. From Humankind:

Since getting his goldendoodle, Mulder, Joe’s life has changed radically.

Mulder is Joe’s service dog. In the index for this book I captured the names of all service dogs, many of which were described in detail. For consistency, Mulder was included, even though the dog is mentioned just this once. Mulder may be a minor character, but there is still something to learn about Mulder.

Besides, I thought, wouldn’t it be wonderful for Joe and his family if they picked up this book and saw that Mulder has a place the index!

So the rule of thumb is that names that are passing mentions are not indexed. This helps keep the index efficient for the reader. But identifying what is a passing mention is always an exercise in judgement.