"archaeostracan" meaning in English

{
  "forms": [
    {
      "form": "archaeostracans",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "archaeostracan (plural archaeostracans)",
      "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"
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          "source": "w"
        },
        {
          "kind": "other",
          "name": "English entries with topic categories using raw markup",
          "parents": [
            "Entries with topic categories using raw markup",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with 1 entry",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "lifeform",
          "langcode": "en",
          "name": "Crustaceans",
          "orig": "en:Crustaceans",
          "parents": [
            "Arthropods",
            "Animals",
            "Lifeforms",
            "All topics",
            "Life",
            "Fundamental",
            "Nature"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "Any extinct crustacean of the order Archaeostraca"
      ],
      "id": "en-archaeostracan-en-noun-ovGn0NGv",
      "links": [
        [
          "extinct",
          "extinct"
        ],
        [
          "crustacean",
          "crustacean"
        ]
      ]
    }
  ],
  "word": "archaeostracan"
}

{
  "forms": [
    {
      "form": "archaeostracans",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "archaeostracan (plural archaeostracans)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        "English countable nouns",
        "English entries with incorrect language header",
        "English entries with topic categories using raw markup",
        "English lemmas",
        "English nouns",
        "Entries using missing taxonomic name (order)",
        "Pages with 1 entry",
        "en:Crustaceans"
      ],
      "glosses": [
        "Any extinct crustacean of the order Archaeostraca"
      ],
      "links": [
        [
          "extinct",
          "extinct"
        ],
        [
          "crustacean",
          "crustacean"
        ]
      ]
    }
  ],
  "word": "archaeostracan"
}