"bajo quinto" meaning in Spanish

{
  "forms": [
    {
      "form": "bajos quintos",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "m"
      },
      "expansion": "bajo quinto m (plural bajos quintos)",
      "name": "es-noun"
    }
  ],
  "lang": "Spanish",
  "lang_code": "es",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "Pages with 2 entries",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Spanish entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "topical",
          "langcode": "es",
          "name": "Musical instruments",
          "orig": "es:Musical instruments",
          "parents": [
            "Music",
            "Tools",
            "Art",
            "Sound",
            "Technology",
            "Culture",
            "Energy",
            "All topics",
            "Society",
            "Nature",
            "Fundamental"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "bajo quinto"
      ],
      "id": "en-bajo_quinto-es-noun-JWtYckK-",
      "links": [
        [
          "music",
          "music"
        ],
        [
          "bajo quinto",
          "bajo quinto#English"
        ]
      ],
      "raw_glosses": [
        "(music) bajo quinto"
      ],
      "tags": [
        "masculine"
      ],
      "topics": [
        "entertainment",
        "lifestyle",
        "music"
      ]
    }
  ],
  "word": "bajo quinto"
}

{
  "forms": [
    {
      "form": "bajos quintos",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "m"
      },
      "expansion": "bajo quinto m (plural bajos quintos)",
      "name": "es-noun"
    }
  ],
  "lang": "Spanish",
  "lang_code": "es",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        "Pages with 2 entries",
        "Pages with entries",
        "Spanish countable nouns",
        "Spanish entries with incorrect language header",
        "Spanish lemmas",
        "Spanish masculine nouns",
        "Spanish multiword terms",
        "Spanish nouns",
        "es:Musical instruments"
      ],
      "glosses": [
        "bajo quinto"
      ],
      "links": [
        [
          "music",
          "music"
        ],
        [
          "bajo quinto",
          "bajo quinto#English"
        ]
      ],
      "raw_glosses": [
        "(music) bajo quinto"
      ],
      "tags": [
        "masculine"
      ],
      "topics": [
        "entertainment",
        "lifestyle",
        "music"
      ]
    }
  ],
  "word": "bajo quinto"
}