"swim fin" meaning in English

{
  "forms": [
    {
      "form": "swim fins",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "swim fin (plural swim fins)",
      "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": "Footwear",
          "orig": "en:Footwear",
          "parents": [
            "Clothing",
            "Human",
            "All topics",
            "Fundamental"
          ],
          "source": "w"
        },
        {
          "kind": "topical",
          "langcode": "en",
          "name": "Swimwear",
          "orig": "en:Swimwear",
          "parents": [
            "Clothing",
            "Swimming",
            "Human",
            "Water sports",
            "All topics",
            "Sports",
            "Fundamental",
            "Human activity",
            "Human behaviour"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "flipper, footwear used while swimming for more speed"
      ],
      "id": "en-swim_fin-en-noun-oZWNg8AB",
      "links": [
        [
          "flipper",
          "flipper"
        ]
      ],
      "synonyms": [
        {
          "word": "swimfin"
        }
      ]
    }
  ],
  "word": "swim fin"
}

{
  "forms": [
    {
      "form": "swim fins",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "swim fin (plural swim fins)",
      "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:Footwear",
        "en:Swimwear"
      ],
      "glosses": [
        "flipper, footwear used while swimming for more speed"
      ],
      "links": [
        [
          "flipper",
          "flipper"
        ]
      ]
    }
  ],
  "synonyms": [
    {
      "word": "swimfin"
    }
  ],
  "word": "swim fin"
}