An HTML element can be annotated with the (boolean) attribute itemscope which indicates that the content of this element and its child elements is about a particular item:
<div itemscope …>
…
</div>
itemscope by itself is rather meaningles because it does not specfy what the conent is about. Therefore, itemscope must be combined with either itemtype or itemref:
The value of itemtype defines a vocabulary about that type. Such a vocabulary basically consists of key-value pairs. The value of the child element's itemprop attribute corresponds to a key, the content of the child element to the value: