What does n mean in a book index?

Factual Questions
1

I came across this in a nonfiction book’s index and don’t know what it means:

nuclear weapons, 15, 221, 281n

Page 281 happens to be an illustration, with no text other than the legends, and there is no mention whatsoever of nuclear weapons on the illustration. So is the n just some sort of typo, or does it have some meaning? I don’t see it anywhere else in the index.

2

My experience is that it indicates that the key word appears in a note rather than in the text itself.

3

From a PDF on indexing standards.

4

I don’t get this. Normally, n means note just as Inner Stickler said. Illustrations are not normally indexed, but in the rare times they are I would expect to see illus.

Oops, I see that you edited your answer.

Dingbang, what do the legends say?

5

Weird. Ethilrist’s post is completely different when I hit the reply button. On the original page, it just quotes my OP and says “asked and answered.” Which didn’t make any sense to me.
But on the reply page, Ethilrist’s post is the cite from a PDF about indexing.

There is no note on that page. The illustration has a few sentences about what was happening on a Navy ship at the time of an accident, but no mention of nuclear weapons.
Okay, full disclosure: It’s my own book from several years ago and a reader just wrote me to ask what the heck that n means. I’d never noticed it before in the index and there’s nothing about that illustration that would make sense to mention nuclear weapons, even in an earlier draft.

6

Sorry about the confusion; from my days as a typesetter, I remembered this as meaning “no text”, which I bolded in your OP in my original reply. I then checked to see if there’s a different usage and, surprise surprise, there is.

However, since, as you say, there’s no text associated with the picture, in this case, perhaps that’s what it means.

7

I’m leaning towards some mistake by the indexer, since n does have some meaning in an index but doesn’t apply to that illustration. So not just a random typo, but a legitimate notation that just doesn’t belong there. Thanks for helping figure that out.