"volume swell" meaning in English

{
  "forms": [
    {
      "form": "volume swells",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "volume swell (plural volume swells)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with 1 entry",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "langcode": "en",
          "name": "Music",
          "orig": "en:Music",
          "parents": [],
          "source": "w"
        }
      ],
      "glosses": [
        "A guitar technique in which a note or chord is played at a muted volume at first and is then faded in slowly."
      ],
      "id": "en-volume_swell-en-noun-1WsPGiYq",
      "links": [
        [
          "music",
          "music"
        ],
        [
          "guitar",
          "guitar"
        ]
      ],
      "raw_glosses": [
        "(music) A guitar technique in which a note or chord is played at a muted volume at first and is then faded in slowly."
      ],
      "synonyms": [
        {
          "word": "violining"
        }
      ],
      "topics": [
        "entertainment",
        "lifestyle",
        "music"
      ]
    }
  ],
  "word": "volume swell"
}

{
  "forms": [
    {
      "form": "volume swells",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "volume swell (plural volume swells)",
      "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:Music"
      ],
      "glosses": [
        "A guitar technique in which a note or chord is played at a muted volume at first and is then faded in slowly."
      ],
      "links": [
        [
          "music",
          "music"
        ],
        [
          "guitar",
          "guitar"
        ]
      ],
      "raw_glosses": [
        "(music) A guitar technique in which a note or chord is played at a muted volume at first and is then faded in slowly."
      ],
      "synonyms": [
        {
          "word": "violining"
        }
      ],
      "topics": [
        "entertainment",
        "lifestyle",
        "music"
      ]
    }
  ],
  "word": "volume swell"
}