"pinaculum" meaning in English

{
  "etymology_text": "From ancient Greek πίναξ (plate) + Latin -ulum.",
  "forms": [
    {
      "form": "pinacula",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "pinacula"
      },
      "expansion": "pinaculum (plural pinacula)",
      "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": "Entomology",
          "orig": "en:Entomology",
          "parents": [
            "Arthropodology",
            "Zoology",
            "Biology",
            "Sciences",
            "All topics",
            "Fundamental"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "A chitin plate on the skin of a caterpillar."
      ],
      "id": "en-pinaculum-en-noun-3bTFyngf",
      "links": [
        [
          "entomology",
          "entomology"
        ],
        [
          "chitin",
          "chitin"
        ],
        [
          "caterpillar",
          "caterpillar"
        ]
      ],
      "raw_glosses": [
        "(entomology) A chitin plate on the skin of a caterpillar."
      ],
      "topics": [
        "biology",
        "entomology",
        "natural-sciences"
      ]
    }
  ],
  "word": "pinaculum"
}

{
  "etymology_text": "From ancient Greek πίναξ (plate) + Latin -ulum.",
  "forms": [
    {
      "form": "pinacula",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "pinacula"
      },
      "expansion": "pinaculum (plural pinacula)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        "English countable nouns",
        "English entries with incorrect language header",
        "English lemmas",
        "English nouns",
        "English nouns with irregular plurals",
        "Pages with 1 entry",
        "Pages with entries",
        "en:Entomology"
      ],
      "glosses": [
        "A chitin plate on the skin of a caterpillar."
      ],
      "links": [
        [
          "entomology",
          "entomology"
        ],
        [
          "chitin",
          "chitin"
        ],
        [
          "caterpillar",
          "caterpillar"
        ]
      ],
      "raw_glosses": [
        "(entomology) A chitin plate on the skin of a caterpillar."
      ],
      "topics": [
        "biology",
        "entomology",
        "natural-sciences"
      ]
    }
  ],
  "word": "pinaculum"
}