"bursa of Fabricius" meaning in English

{
  "etymology_text": "Named after Hieronymus Fabricius, who described it in 1621.",
  "forms": [
    {
      "form": "bursae of Fabricius",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "bursae of Fabricius"
      },
      "expansion": "bursa of Fabricius (plural bursae of Fabricius)",
      "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": "other",
          "name": "Pages with 1 entry",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "topical",
          "langcode": "en",
          "name": "Zoology",
          "orig": "en:Zoology",
          "parents": [
            "Biology",
            "Sciences",
            "All topics",
            "Fundamental"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "A glandular sac opening into the cloaca of a bird, producing B cells."
      ],
      "id": "en-bursa_of_Fabricius-en-noun-pGeV3JU7",
      "links": [
        [
          "zoology",
          "zoology"
        ],
        [
          "glandular",
          "glandular"
        ],
        [
          "cloaca",
          "cloaca"
        ],
        [
          "B cell",
          "B cell"
        ]
      ],
      "raw_glosses": [
        "(zoology) A glandular sac opening into the cloaca of a bird, producing B cells."
      ],
      "topics": [
        "biology",
        "natural-sciences",
        "zoology"
      ]
    }
  ],
  "word": "bursa of Fabricius"
}

{
  "etymology_text": "Named after Hieronymus Fabricius, who described it in 1621.",
  "forms": [
    {
      "form": "bursae of Fabricius",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "bursae of Fabricius"
      },
      "expansion": "bursa of Fabricius (plural bursae of Fabricius)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        "English countable nouns",
        "English entries with incorrect language header",
        "English eponyms",
        "English lemmas",
        "English multiword terms",
        "English nouns",
        "Pages with 1 entry",
        "Pages with entries",
        "en:Zoology"
      ],
      "glosses": [
        "A glandular sac opening into the cloaca of a bird, producing B cells."
      ],
      "links": [
        [
          "zoology",
          "zoology"
        ],
        [
          "glandular",
          "glandular"
        ],
        [
          "cloaca",
          "cloaca"
        ],
        [
          "B cell",
          "B cell"
        ]
      ],
      "raw_glosses": [
        "(zoology) A glandular sac opening into the cloaca of a bird, producing B cells."
      ],
      "topics": [
        "biology",
        "natural-sciences",
        "zoology"
      ]
    }
  ],
  "word": "bursa of Fabricius"
}