{
  "@context" : [ "http://cambridgesemantics.com/ontologies/2018/06/MetadataDictionary/ClassConcept", "http://cambridgesemantics.com/ontologies/2018/06/MetadataDictionary/PrimaryKey", "http://cambridgesemantics.com/ontologies/2018/06/MetadataDictionary/MetadataDictionary" ],
  "@graph" : [ {
    "uri" : "http://test1",
    "type" : "metaframe:MetadataDictionary",
    "metaDataConcepts" : {
      "uri" : "http://testc1",
      "type" : "metaframe:ClassConcept",
      "primaryKey" : [ {
        "uri" : "http://pk1",
        "type" : "metaframe:PrimaryKey",
        "priority" : "5"
      }, {
        "uri" : "http://pk2",
        "type" : "metaframe:PrimaryKey",
        "priority" : "6"
      } ]
    },
    "title" : "test1"
  }, {
    "uri" : "http://test2",
    "type" : "metaframe:MetadataDictionary",
    "title" : "test2"
  } ]
}

2.3.4 Omit graph flag
The omit graph flag determines if framed output containing a single node object is contained within @graph, or not. The initial value for the omit graph flag is set using the omitGraph option, or based on the processing mode; if processing mode is json-ld-1.0, the output always includes a @graph member, otherwise, the @graph member is used only to describe multiple node objects, consistent with compaction. See § 4.2.2 Framing Algorithm for a further discussion.