A can opener (in North American English and Australian English) or tin opener (used in British English) is a mechanical device used to open tin cans (metal cans). Although preservation of food using tin cans had been practiced since at least 1772 in the Netherlands, the first can openers were not patented until 1855 in England and 1858 in the United States.

The first cans were robust containers, which weighed more than the food they contained and required ingenuity to open, using whatever tools available. The instruction on those cans read "Cut round the top near the outer edge with a chisel and hammer." The gap of decades between the invention of the can and can opener may be attributed to the functionality of existing tools versus the cost and effort of a new tool.

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