"rock maple" meaning in English

{
  "etymology_text": "From the hardness of its wood relative to the wood of other maples.",
  "forms": [
    {
      "form": "rock maples",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "rock maple (plural rock maples)",
      "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 topic categories using raw markup",
          "parents": [
            "Entries with topic 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"
        },
        {
          "kind": "lifeform",
          "langcode": "en",
          "name": "Maples",
          "orig": "en:Maples",
          "parents": [
            "Soapberry family plants",
            "Trees",
            "Sapindales order plants",
            "Shrubs",
            "Plants",
            "Lifeforms",
            "All topics",
            "Life",
            "Fundamental",
            "Nature"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "The sugar maple, Acer saccharum."
      ],
      "id": "en-rock_maple-en-noun-yBvn9egz",
      "links": [
        [
          "sugar maple",
          "sugar maple"
        ],
        [
          "Acer saccharum",
          "Acer saccharum#Translingual"
        ]
      ],
      "synonyms": [
        {
          "sense": "Acer saccharum",
          "word": "hard maple"
        }
      ]
    }
  ],
  "word": "rock maple"
}

{
  "etymology_text": "From the hardness of its wood relative to the wood of other maples.",
  "forms": [
    {
      "form": "rock maples",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "rock maple (plural rock maples)",
      "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 multiword terms",
        "English nouns",
        "English terms with non-redundant non-automated sortkeys",
        "en:Maples"
      ],
      "glosses": [
        "The sugar maple, Acer saccharum."
      ],
      "links": [
        [
          "sugar maple",
          "sugar maple"
        ],
        [
          "Acer saccharum",
          "Acer saccharum#Translingual"
        ]
      ]
    }
  ],
  "synonyms": [
    {
      "sense": "Acer saccharum",
      "word": "hard maple"
    }
  ],
  "word": "rock maple"
}