A keyword is not a controlled vocabulary. Expect any value. These are used in the subject properties to identify keywords for images.
Example:
subject: [
{
code: "new york rangers",
name: "New York Rangers",
scheme: "http://tt.se/spec/keyword/1.0"
},
{
code: "nhl",
name: "NHL",
scheme: "http://tt.se/spec/keyword/1.0"
},
{
code: "ishockey",
name: "ishockey",
scheme: "http://tt.se/spec/keyword/1.0"
},
{
code: "målvakt",
name: "målvakt",
scheme: "http://tt.se/spec/keyword/1.0"
}
]