The Piggy bank reference article from the English Wikipedia on 24-Apr-2004
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Piggy bank

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Piggy bank (sometimes penny bank) is the traditional name of a coin accumulation and storage container, most often used by children. It is often shaped like a pig; sometimes it must be smashed in order to retrieve the coins.

The etymology of the name is curious: in Middle English, "pygg" referred to a type of clay used for making various household objects such as jars. People saved money in kitchen potss and jars made of pygg, called "pygg jars". By the 18th Century, the term "pygg jar" had evolved to "pig bank".