I was looking through the working of VF page I read that it save the instruction as metadata. Can any body explain me in simple words that what is metadata.
Metadata is basically “data that describes other data”.
For example, in Salesforce you can query data like this:
SELECT FirstName FROM Contact WHERE FirstName='Mike'
Salesforce also provides metadata tables that describe code and configuration:
SELECT Id FROM ApexClass WHERE ApiVersion < 25
The Metadata API provides even more detail about code, objects, profiles, reports, and many more items
The Force.com IDE for Eclipse plug-in uses the Metadata API to keep local files in sync with Salesforce.