"busy signal" meaning in Anglais

{
  "categories": [
    {
      "kind": "other",
      "name": "Compositions en anglais",
      "parents": [],
      "source": "w"
    },
    {
      "kind": "other",
      "name": "Lexique en anglais des télécommunications",
      "parents": [],
      "source": "w"
    },
    {
      "kind": "other",
      "name": "Locutions nominales en anglais",
      "parents": [],
      "source": "w"
    },
    {
      "kind": "other",
      "name": "Anglais",
      "orig": "anglais",
      "parents": [],
      "source": "w"
    }
  ],
  "etymology_texts": [
    "Composé de busy et de signal."
  ],
  "forms": [
    {
      "form": "busy signals",
      "tags": [
        "plural"
      ]
    }
  ],
  "lang": "Anglais",
  "lang_code": "en",
  "pos": "noun",
  "pos_title": "Locution nominale",
  "related": [
    {
      "word": "dial tone"
    }
  ],
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "Lexique en anglais de la téléphonie",
          "parents": [],
          "source": "w"
        }
      ],
      "glosses": [
        "Tonalité d’occupation."
      ],
      "id": "fr-busy_signal-en-noun-4UECQNKf",
      "topics": [
        "telephony"
      ]
    }
  ],
  "synonyms": [
    {
      "word": "busy tone"
    }
  ],
  "word": "busy signal"
}

{
  "categories": [
    "Compositions en anglais",
    "Lexique en anglais des télécommunications",
    "Locutions nominales en anglais",
    "anglais"
  ],
  "etymology_texts": [
    "Composé de busy et de signal."
  ],
  "forms": [
    {
      "form": "busy signals",
      "tags": [
        "plural"
      ]
    }
  ],
  "lang": "Anglais",
  "lang_code": "en",
  "pos": "noun",
  "pos_title": "Locution nominale",
  "related": [
    {
      "word": "dial tone"
    }
  ],
  "senses": [
    {
      "categories": [
        "Lexique en anglais de la téléphonie"
      ],
      "glosses": [
        "Tonalité d’occupation."
      ],
      "topics": [
        "telephony"
      ]
    }
  ],
  "synonyms": [
    {
      "word": "busy tone"
    }
  ],
  "word": "busy signal"
}