"hamar" meaning in Old Norse

{
  "head_templates": [
    {
      "args": {
        "1": "non",
        "2": "noun form"
      },
      "expansion": "hamar",
      "name": "head"
    }
  ],
  "lang": "Old Norse",
  "lang_code": "non",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "Old Norse entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        }
      ],
      "form_of": [
        {
          "word": "hamarr"
        }
      ],
      "glosses": [
        "accusative singular of hamarr"
      ],
      "id": "en-hamar-non-noun-vJyJKG0v",
      "links": [
        [
          "hamarr",
          "hamarr#Old Norse"
        ]
      ],
      "tags": [
        "accusative",
        "form-of",
        "singular"
      ]
    }
  ],
  "word": "hamar"
}

{
  "categories": [
    "Old Swedish a-stem nouns",
    "Old Swedish entries with incorrect language header",
    "Old Swedish lemmas",
    "Old Swedish masculine nouns",
    "Old Swedish nouns",
    "Old Swedish terms derived from Old Norse",
    "Old Swedish terms derived from Proto-Germanic",
    "Old Swedish terms inherited from Old Norse",
    "Old Swedish terms inherited from Proto-Germanic",
    "Pages using bad params when calling Template:gmq-osw-decl-noun-a-m"
  ],
  "head_templates": [
    {
      "args": {
        "1": "non",
        "2": "noun form"
      },
      "expansion": "hamar",
      "name": "head"
    }
  ],
  "lang": "Old Norse",
  "lang_code": "non",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        "Old Norse entries with incorrect language header",
        "Old Norse non-lemma forms",
        "Old Norse noun forms"
      ],
      "form_of": [
        {
          "word": "hamarr"
        }
      ],
      "glosses": [
        "accusative singular of hamarr"
      ],
      "links": [
        [
          "hamarr",
          "hamarr#Old Norse"
        ]
      ],
      "tags": [
        "accusative",
        "form-of",
        "singular"
      ]
    }
  ],
  "word": "hamar"
}