"silent alarm" meaning in English

{
  "forms": [
    {
      "form": "silent alarms",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "silent alarm (plural silent alarms)",
      "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": "English oxymorons",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Entries with translation boxes",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with 1 entry",
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          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "topical",
          "langcode": "en",
          "name": "Crime prevention",
          "orig": "en:Crime prevention",
          "parents": [
            "Crime",
            "Public safety",
            "Criminal law",
            "Society",
            "Public administration",
            "Security",
            "Law",
            "All topics",
            "Government",
            "Justice",
            "Fundamental",
            "Politics"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "A burglar alarm that makes no noise that is audible to the trespasser."
      ],
      "id": "en-silent_alarm-en-noun-hR9-Fj3-",
      "links": [
        [
          "burglar alarm",
          "burglar alarm"
        ]
      ]
    }
  ],
  "word": "silent alarm"
}

{
  "forms": [
    {
      "form": "silent alarms",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "silent alarm (plural silent alarms)",
      "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",
        "English oxymorons",
        "Entries with translation boxes",
        "Pages with 1 entry",
        "Pages with entries",
        "Translation table header lacks gloss",
        "en:Crime prevention"
      ],
      "glosses": [
        "A burglar alarm that makes no noise that is audible to the trespasser."
      ],
      "links": [
        [
          "burglar alarm",
          "burglar alarm"
        ]
      ]
    }
  ],
  "word": "silent alarm"
}