RDF documents are made of RDF statements that describe resources. Each statement has three parts, so it's called a triple. Here are the three parts of an RDF statement:
A resource. Resources are typically Web documents that you point to with a URI.
A named property. Such a property is a specific characteristic or attribute of the resource, such as the resource's creator.
A property value. The value of the property is the property's content. For example, the value of the <Creator> property is usually the name of the resource's creator.
An RDF statement, then, is made up of a resource, a named property, and a property value. In RDF, you name these three parts like this:
The resource is called the subject of the statement.
The named property ...