When you ask an expert to explain meta-data, they're likely to start their explanation by telling you that meta-data is "data about data." For many, this phrase makes the topic even more perplexing. The key to understanding the phrase "data about data" is to recognize that the second "data" is the thing being described.

 

The idea of meta-data originated as a way for programmers to refer to information about data sets, but is now applied more broadly to refer to any standardized information about both digital and non-digital resources.

Calling these resources data is in many cases literally correct but not the way most people think. Here are some examples to help make it more concrete.