"Schreger line" meaning in English

{
  "forms": [
    {
      "form": "Schreger lines",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "Schreger line (plural Schreger lines)",
      "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": "English entries with language name categories using raw markup",
          "parents": [
            "Entries with language name categories using raw markup",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "English terms with non-redundant non-automated sortkeys",
          "parents": [
            "Terms with non-redundant non-automated sortkeys",
            "Entry maintenance"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "A line-like visual artifact that is evident in the cross-sections of ivory."
      ],
      "id": "en-Schreger_line-en-noun-CZ4vRv9y",
      "links": [
        [
          "cross-section",
          "cross-section"
        ],
        [
          "ivory",
          "ivory"
        ]
      ],
      "wikipedia": [
        "Schreger line"
      ]
    }
  ],
  "word": "Schreger line"
}

{
  "forms": [
    {
      "form": "Schreger lines",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "Schreger line (plural Schreger lines)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        "English countable nouns",
        "English entries with incorrect language header",
        "English entries with language name categories using raw markup",
        "English eponyms",
        "English lemmas",
        "English multiword terms",
        "English nouns",
        "English terms with non-redundant non-automated sortkeys"
      ],
      "glosses": [
        "A line-like visual artifact that is evident in the cross-sections of ivory."
      ],
      "links": [
        [
          "cross-section",
          "cross-section"
        ],
        [
          "ivory",
          "ivory"
        ]
      ],
      "wikipedia": [
        "Schreger line"
      ]
    }
  ],
  "word": "Schreger line"
}