A Schema.org Type categorizes entities as specific kinds of things. For example, the ‘Person’ type is used to represent individuals who are “alive, dead, undead, or fictional”, while the ‘Product’ type represents an entity that is available for purchase. In the image of Schema.org’s full Type hierarchy below, we can see that ‘Thing’ is at the top since it’s the broadest category. Person is a subtype of Thing, and Patient is a subtype of Person. Not only does a Type categorize an entity, it also defines which properties can be used to describe that entity, or link it to other entities. You can click on a Type to see its definition and what properties are available to it. Here’s the page that represents the Person Type. Each Type has the following pieces of information:
Name. The name of the type.
Where the Type fits into Schema.org’s hierarchy. In this case a Person is a subtype of ‘Thing’.
A definition. This tells you what the Type should apply to. For example, Schema.org’s definition of Person states that it can be applied to ‘A person’ who is ‘alive, dead, undead, or fictional’.
Properties. Each Type has a list of available properties to further describe it. In the image below we see that the Person Type is further described with properties like address, alumniOf, and birthDate.
Expected Types for properties. Each property also has a Type (or Types) it can connect to. For example, a Person has an address property. This information can either be added as plain text, or it can be used to link to an entity typed as PostalAddress, which has its own page in Schema.org.