"orphan receptor" meaning in English

{
  "forms": [
    {
      "form": "orphan receptors",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "orphan receptor (plural orphan receptors)",
      "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"
        },
        {
          "kind": "topical",
          "langcode": "en",
          "name": "Physiology",
          "orig": "en:Physiology",
          "parents": [
            "Biology",
            "Medicine",
            "Sciences",
            "All topics",
            "Fundamental"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "A receptor that has a similar structure to other identified receptors but whose endogenous ligand has not yet been identified"
      ],
      "id": "en-orphan_receptor-en-noun-80rOyQa5",
      "links": [
        [
          "physiology",
          "physiology"
        ],
        [
          "endogenous",
          "endogenous"
        ],
        [
          "ligand",
          "ligand"
        ]
      ],
      "raw_glosses": [
        "(physiology) A receptor that has a similar structure to other identified receptors but whose endogenous ligand has not yet been identified"
      ],
      "related": [
        {
          "word": "deorphanized"
        }
      ],
      "topics": [
        "medicine",
        "physiology",
        "sciences"
      ],
      "wikipedia": [
        "orphan receptor"
      ]
    }
  ],
  "word": "orphan receptor"
}

{
  "forms": [
    {
      "form": "orphan receptors",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "orphan receptor (plural orphan receptors)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "related": [
    {
      "word": "deorphanized"
    }
  ],
  "senses": [
    {
      "categories": [
        "English countable nouns",
        "English entries with incorrect language header",
        "English lemmas",
        "English multiword terms",
        "English nouns",
        "en:Physiology"
      ],
      "glosses": [
        "A receptor that has a similar structure to other identified receptors but whose endogenous ligand has not yet been identified"
      ],
      "links": [
        [
          "physiology",
          "physiology"
        ],
        [
          "endogenous",
          "endogenous"
        ],
        [
          "ligand",
          "ligand"
        ]
      ],
      "raw_glosses": [
        "(physiology) A receptor that has a similar structure to other identified receptors but whose endogenous ligand has not yet been identified"
      ],
      "topics": [
        "medicine",
        "physiology",
        "sciences"
      ],
      "wikipedia": [
        "orphan receptor"
      ]
    }
  ],
  "word": "orphan receptor"
}