"common knowledge" meaning in English

{
  "etymology_text": ": common knowledge < → δείτε τις λέξεις common και knowledge",
  "forms": [
    {
      "form": "common knowledge"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "phrase",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "Ιδιωματισμοί (αγγλικά)",
          "parents": [],
          "source": "w"
        }
      ],
      "examples": [
        {
          "text": "It’s common knowledge that the prime minister will introduce a new law in parliament.",
          "translation": "Είναι κοινή γνώση πως ο πρωθυπουργός θα φέρει νέο νόμο στο κοινοβούλιο."
        }
      ],
      "glosses": [
        "κοινή γνώση"
      ],
      "id": "el-common_knowledge-en-phrase-vF4Lk~Lr",
      "raw_tags": [
        "ιδιωματισμός"
      ]
    }
  ],
  "word": "common knowledge"
}

{
  "etymology_text": ": common knowledge < → δείτε τις λέξεις common και knowledge",
  "forms": [
    {
      "form": "common knowledge"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "phrase",
  "senses": [
    {
      "categories": [
        "Ιδιωματισμοί (αγγλικά)"
      ],
      "examples": [
        {
          "text": "It’s common knowledge that the prime minister will introduce a new law in parliament.",
          "translation": "Είναι κοινή γνώση πως ο πρωθυπουργός θα φέρει νέο νόμο στο κοινοβούλιο."
        }
      ],
      "glosses": [
        "κοινή γνώση"
      ],
      "raw_tags": [
        "ιδιωματισμός"
      ]
    }
  ],
  "word": "common knowledge"
}