"grease pencil" meaning in English

{
  "forms": [
    {
      "form": "grease pencils",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "grease pencil (plural grease pencils)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with 1 entry",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "langcode": "en",
          "name": "Writing instruments",
          "orig": "en:Writing instruments",
          "parents": [],
          "source": "w"
        }
      ],
      "glosses": [
        "A wax-based pencil used for writing on shiny surfaces."
      ],
      "id": "en-grease_pencil-en-noun-vIyHtTCp",
      "links": [
        [
          "wax",
          "wax"
        ],
        [
          "pencil",
          "pencil"
        ],
        [
          "writing",
          "writing"
        ],
        [
          "shiny",
          "shiny"
        ],
        [
          "surface",
          "surface"
        ]
      ],
      "synonyms": [
        {
          "word": "china pencil"
        },
        {
          "english": "brand name",
          "word": "chinagraph"
        },
        {
          "word": "wax pencil"
        }
      ]
    }
  ],
  "word": "grease pencil"
}

{
  "forms": [
    {
      "form": "grease pencils",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "grease pencil (plural grease pencils)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        "English countable nouns",
        "English entries with incorrect language header",
        "English lemmas",
        "English multiword terms",
        "English nouns",
        "Pages with 1 entry",
        "Pages with entries",
        "en:Writing instruments"
      ],
      "glosses": [
        "A wax-based pencil used for writing on shiny surfaces."
      ],
      "links": [
        [
          "wax",
          "wax"
        ],
        [
          "pencil",
          "pencil"
        ],
        [
          "writing",
          "writing"
        ],
        [
          "shiny",
          "shiny"
        ],
        [
          "surface",
          "surface"
        ]
      ]
    }
  ],
  "synonyms": [
    {
      "word": "china pencil"
    },
    {
      "english": "brand name",
      "word": "chinagraph"
    },
    {
      "word": "wax pencil"
    }
  ],
  "word": "grease pencil"
}