A lossy data conversion method is one where converting data between one storage format and another displays data in a form that is "close enough" to be useful, but may differ in some ways from the original. This type of conversion is used frequently between software packages that rely on different storage techniques. In many cases, a software package such as Microsoft Word will enable a document stored in one format to be saved as another, in particular HTML. The document saved in the lossy format may look identical, but the conversion can also cause some loss of fidelity or functionality.
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