The term etch has two related meanings. Originally, it referred to a step in the production of a printed circuit board. It has now come to mean a particular version of a given board; i.e. if an ECO is made to a particular type of board, via a change to the image which is etched into the card (so that the fix will automatically be present in new production), the new version is termed 'a different etch'. Documentation will often explicitly label the various etch revisions of a card.