Metadata is simply data about data. It means it is a description and context of the data. It helps to organize, find and understand data. Here are a few real world examples of metadata: Typical metadata. Those are some typical metadata elements: Title and description, Tags and categories, Who created and when, Who last modified and when, More @Wikipedia
Hover over any link to get a description of the article. Please note that search keywords are sometimes hidden within the full article and don't appear in the description or title.