"call tree" meaning in English

{
  "forms": [
    {
      "form": "call trees",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "call tree (plural call trees)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "A hierarchy or tree of people (employees, students etc.) in which each person forwards a message to the next person down the line. The tree is arranged so that a single person can easily forward messages to all people."
      ],
      "id": "en-call_tree-en-noun-XoNTF4Kg",
      "links": [
        [
          "hierarchy",
          "hierarchy"
        ],
        [
          "tree",
          "tree"
        ],
        [
          "employee",
          "employee"
        ],
        [
          "student",
          "student"
        ]
      ],
      "synonyms": [
        {
          "word": "phone tree"
        }
      ],
      "translations": [
        {
          "code": "nl",
          "lang": "Dutch",
          "sense": "tree of people in which each person forwards a message to the next person",
          "tags": [
            "masculine"
          ],
          "word": "telefoonboom"
        }
      ]
    }
  ],
  "word": "call tree"
}

{
  "forms": [
    {
      "form": "call trees",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "call tree (plural call trees)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        "English countable nouns",
        "English entries with incorrect language header",
        "English lemmas",
        "English multiword terms",
        "English nouns"
      ],
      "glosses": [
        "A hierarchy or tree of people (employees, students etc.) in which each person forwards a message to the next person down the line. The tree is arranged so that a single person can easily forward messages to all people."
      ],
      "links": [
        [
          "hierarchy",
          "hierarchy"
        ],
        [
          "tree",
          "tree"
        ],
        [
          "employee",
          "employee"
        ],
        [
          "student",
          "student"
        ]
      ],
      "synonyms": [
        {
          "word": "phone tree"
        }
      ]
    }
  ],
  "translations": [
    {
      "code": "nl",
      "lang": "Dutch",
      "sense": "tree of people in which each person forwards a message to the next person",
      "tags": [
        "masculine"
      ],
      "word": "telefoonboom"
    }
  ],
  "word": "call tree"
}