A vocabulary of landscape — a landscape of words 1323 entries

foxed

FOKST
Foxed describes paper marked with the small rust-brown spots that appear on old books, prints, and maps, usually scattered across the margins and the endpapers. Booksellers use the word as a condition term, so a description reading lightly foxed is telling you what to expect before the parcel arrives. The spots come from some combination of mold growing in damp paper and iron impurities in the pulp oxidizing.
Etymology
The name is for the color, which is the reddish brown of a fox. English does this often enough to be a habit, using the animal as a color word in foxy for a red-brown coat and in the horse color sorrel, which came in from French for the same shade. The unrelated foxed meaning baffled is a separate word, from the fox as a byword for cunning.
Notes
Foxing is not straightforwardly reversible, and conservators generally stabilize the paper rather than attempt to remove the marks. Handmade rag paper made before the nineteenth century foxes less than machine-made wood pulp paper, which is why an eighteenth-century book often looks better than a Victorian one.