Data Processing is any process that converts data into information. The processing is usually assumed to be automated and running on an electronic computer.
In this context data is defined as a collection of numbers or characters that represent a measurement from the real world. Information is defined as a meaningful answer to a query.
More generally, the term data processing can apply to any process that converts data from one format to another, although data conversion would be the more logical and correct term. The distinction is that conversion doesn't require a question to be answered.