I ordered a book online, unseen, and the invoice told me the book, or at least its pages, were 'foxed'. I had never come across the expression, did not know the word could be a verb and discovered :

Foxing is the age related browning, or brown-yellowish spots, that can occur to book paper over time. When this aging process happens to the paper in a book it is referred to as "foxed".

The term may come from the rust brown color of the paper aging process or from a chemical used to coat paper called ferric oxide. Foxing may also be caused by fungal growth on the paper, chemical reactions, or high humidity.


Is there any more information anywhere to clarify the idea of ferric oxide being involved, which sounds a little far-fetched to me, or to demonstrate the history of the word in that particular context?


3 Answers 3


For your consideration, I submit to you neither ferric oxide nor foxes, but rather mold . . .

Folk-Etymology: A Dictionary of Verbal Corruptions Or Words Perverted in Form Or Meaning, by False Derivation Or Mistaken Analogy (Abram Smythe Palmer, 1890) offers this:

FOXED. A print or book is said to be foxed, when the paper has become spotted or discoloured by damp. In Warwickshire the same term is applied to timber when discoloured by incipient decay. It is, no doubt, the same word as the West country foust, soiled, mouldy, and fust, to become moldy, Scot. foze, the same. Compare fouse, a Craven form of fox. Fust is from O. Fr. fusté, “fusty,” originally smelling of the cask (fust, from Lat. fustis). “They stanke like fustie barrells.”—Nash, Pierce Penilesse, p. 33.

Following the mold theme, we find inside 1993’s Conservation Administration News an article titled “The Great Foxing Debate” by Karl R. Schaefer. Until I can access a library copy, I have used Google Books to piece together some snippets here:

While the phenomenon has been observed and remarked upon for well over a century, the cause of the spots or stains has been the subject of considerable debate among antiquarians, conservators, librarians, booksellers, chemists, and biologists . . .

The term we are most likely to encounter today is “foxing,” but the form “foxed” is slightly older and may provide a clue as to the original meaning of the term as it applies to books. The etymology of Lydenberg and Archer is the one most frequently cited. They claim the term refers to Reynard the Fox, whose rusty red color is similar to the color of the stains on foxed pages. This explanation seems rather specious; it appears to make sense because of the characteristic colors of the stains, but I suspect a stronger relationship than simply one of color. . . .

[OED entries referenced here] It is interesting that two of the meanings listed — three if one uses a little poetic license — have to do with souring or rotting. In addition, one of the meanings of the somewhat later term “foxing” is a growth of mold or bacteria in a vat of sour beer. It may very well be that booksellers, librarians, or book owners borrowed the term “foxed” from the brewer or the ale man . . .

I would suggest that a more likely explanation for the origin of the terms “foxed” and “foxing,” as they apply to books, is that the terms were understood to refer to the odor which arose from the mold, rather than to its color. Or, more likely still, it implied both color and odor. In support of this argument, Harrison mentions a “peculiar odor” (page 166) emanating from foxed books. Such an observation, however casual, lends weight to the case for a reexamination of the etymology of the word. (How the brewers came to use the term is beyond the scope of this article, but the possibility of a connection certainly warrants further investigation. [ed. note: see Palmer, above]) . . . As noted above, the term itself may very well suggest some sort of souring or decay.

Lastly, here’s a roundup of fox mold in action from the OED:

3. Of the leaves of books, also of timber; Discoloured by decay; stained with brownish-yellow spots.
1847   Timber is said to be foxed, when it becomes discoloured in consequence of incipient decay. Warw.
1848   A torn or foxt and dog's-eared volume.

paper mildew
1937   Foxed, foxing or foxy, stains, specks or spots in paper, e.g. prints, books, mostly due to mould or paper-mildew.

1935   The so-called ‘foxy’ appearance of paper caused by the oxidising action of mould fungi or chemical processes of oxidation.

1958   First a word on ‘fox-marks’. These brown stains..are caused by damp.

Source: Oxford English Dictionary (login required)

  • Damp . . . moldy . . . . 'fustie' . . . . . foxy . . . . . has a definite appeal, I have to confess.
    – Nigel J
    Nov 11 at 3:49

In the article about foxing of the American Institute for Conservation's (AIC) Wiki it is written that

[t]he term foxing is derived from the rusty red color of Reynard the fox and its use was first noted in 1848 (Meynell and Newsam 1979, 567).

The referenced article can be found here, however I can only access the preview which has no mentioning regarding the naming or the year 1848. @Tinfoil Hat further confirmed that neither in the mentioned article not in the other referenced works of Meynell there is any mentioning of Reynard the fox. Apparently this is a misreference in the article.

However another one of the AIC Wiki's article references, "Notes on the Causes and Prevention of Foxing in Books" by Thomas M. Iiams and T. D. Beckwith, published in 1935, contains more or less the identical wording used in the article. Immediately on the first page, available as a free preview, it states:

Not infrequently on old paper, less commonly on modern stocks, one finds a dull rusty patch discoloring the page in annoying fashion. This is due to ‘foxing’, the term going back to the rusty red of Reynard the Fox.

Yet no more reference or explanation is given.

  • 1
    I accessed the referenced “Meynell and Newsam 1979, 567” and there is no sign of Reynard the fox, nor is there any sign of him in the other Meynell cites. I think the cite is attached to the wrong sentence. Nov 9 at 2:32
  • Thanks for checking. I updated the answer accordingly.
    – Christoph
    Nov 10 at 12:26

Arthur Lee Humphreys in the 1897 book The Private Library: What We Do Know, What We Don't Know, What We Ought to Know About Our Books (Google Books) describes books as being foxey and foxed, indicating discoloration:

When a book is spotted it is called 'foxed,' and these 'foxey' books are for the most part books printed in the early part of this century, when paper-makers first discovered they could bleach their rags, and, owing to the inefficient means used to neutralize the bleach, the book carried the seeds of decay in itself, and when exposed to any damp soon became discoloured with brown stains. A foxed book cannot have the fox marks removed, and such a book should be avoided.

The impurities left as paper was bleached would be in the paper itself. These impurities would have included both organic material and iron, which would rust (hence ferric oxide; see ABAA for a fuller explanation).

Hunting the term back in time, I find a reference in Thomas Frognall's 1811 book Bibliomania (Google Books):

All the copies of Chevillier's book, which I have seen, are printed upon what is called Foxey paper.

The word likely means ruddy or reddish-brown, referring to the fox's fur. The French term roux or rousse, referring to hair, is glossed as foxey in Abel Boyer's Anglo-French dictionary from 1792 (Google Books):

ROUX, ROUSSE, adj. (de couleur entre rouge et jaune.) Red or ruddy. Roux, (qui a le poil roux.) Redhaired, carroty, or foxey. Papier roux. Brown paper. Beurre roux, (devenu roux à la poêle.) Brown or burnt butter.

  • 3
    I would think that "fox" was derived from "ferrous oxide".
    – jrw32982
    Nov 8 at 21:20
  • 3
    @jrw32982: I might have thought that too, but the full OED has a 1611 citation Before they parted they foxt Tarlton at the Castle in Pater Noster Row (where "foxed" = "red-nosed from booze"). Unlike "mox" today, perhaps, the popular tongue would never have taken to "ferrous oxide" back then! Figurative usage deriving from Reynard's colour, that's all. Nov 8 at 23:03
  • 3
    I can’t find any reference to ferric oxide in print before 1875. So if that chemical term was not in use before the book term fox* came about, that suggests it could not have come from ferric oxide. Nov 8 at 23:04
  • 1
    Also — just to throw another “iron” into the fire — your ABBA reference shows under Related Information: “foxing…. The name, first recorded in the middle of the nineteenth century, comes from the observations that it looked as if a fox with muddy paws had trampled across the page.” Nov 9 at 3:26
  • My knowledge of the history of chemistry is rudimentary; but I would imagine even the experts would not have understood the process of oxidation back then. Oxygen was only discovered in 1774 but was thought at the time to be the substance which produces acids (hence the name oxygen). This was demonstrated to have been false in 1812 (or thereabouts) but it's unlikely that this knowledge would have permeated society a few mere decades later, enough to have been used casually in printing.
    – tripleee
    Nov 9 at 11:32

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