Definition of term:: Foxing

  • Foxing
    Spotting on a book, usually brown spots found on paper, of varying severity, caused by a chemical action wherein impurities in the paper oxidize. This is often exacerbated by an excessively humid climate, but the "cause" is the composition of the paper itself, and some books are simply more prone to foxing than others.
Source: What bookdealers really mean. A dictionary by Tom Congalton and Dan Gregory (Between the Covers), with additions from other sources