[1]

Web Annotation Data Model (2017-02-24 02:14:26 +09:00) https://w3c.github.io/web-annotation/model/wd2/#dfn-property

Property
A feature of a Resource, that often has a particular data type. In the model sections, the term "Property" is used to refer to only those features which are not Relationships and instead have a literal value such as a string, integer or date. The valid values for a Property are thus any data type other than object, or an array containing members of that data type if more than one is allowed.

[2]

Selectors and States (2017-02-24 02:14:26 +09:00) https://w3c.github.io/web-annotation/selector-note/#dfn-property

Property
A feature of a Resource, that often has a particular data type. In the model sections, the term "Property" is used to refer to only those features which are not Relationships and instead have a literal value such as a string, integer, or date. The valid values for a Property are thus any data type other than object, or an array containing members of that data type if more than one is allowed.