So many ways in which American English is slightly different from my English. We say railway, you say railroad, we say sleeper, you say tie. Fish came from fiche [as in microfiche]- a plate, and not from haddock and the like! To me, a flitch is a dod of wood squared up for re-sawing or an uncut side of bacon.
http://en.wikipedia.org/wiki/Fishplate shows the plates in their many guises.
