Orig. a footstool; then a table displaying wares for sale, most often meat; later, a street or passage of such tables, a meat market, e.g. the Shambles in York, whence our use of the word to indicate disorder. Shambles was known in 12c Latin as carnificium, a word used also of butchery. [< OldEngl. sceamul, scamol = footstool] -
Cf. Chepe
Dictionary of Medieval Terms and Phrases. Christopher Coredon with Ann Williams.