"buoyancy aid" meaning in English

{
  "forms": [
    {
      "form": "buoyancy aids",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "buoyancy aid (plural buoyancy aids)",
      "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"
        }
      ],
      "glosses": [
        "A waterproof device in the form of a jacket, which stops one from sinking in water."
      ],
      "id": "en-buoyancy_aid-en-noun-Bob0-8qv",
      "links": [
        [
          "waterproof",
          "waterproof"
        ],
        [
          "jacket",
          "jacket"
        ]
      ],
      "translations": [
        {
          "code": "is",
          "lang": "Icelandic",
          "sense": "jacket",
          "tags": [
            "masculine"
          ],
          "word": "flotbúnaður"
        }
      ]
    }
  ],
  "word": "buoyancy aid"
}

{
  "forms": [
    {
      "form": "buoyancy aids",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "buoyancy aid (plural buoyancy aids)",
      "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"
      ],
      "glosses": [
        "A waterproof device in the form of a jacket, which stops one from sinking in water."
      ],
      "links": [
        [
          "waterproof",
          "waterproof"
        ],
        [
          "jacket",
          "jacket"
        ]
      ]
    }
  ],
  "translations": [
    {
      "code": "is",
      "lang": "Icelandic",
      "sense": "jacket",
      "tags": [
        "masculine"
      ],
      "word": "flotbúnaður"
    }
  ],
  "word": "buoyancy aid"
}