"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 entries with language name categories using raw markup",
          "parents": [
            "Entries with language name categories using raw markup",
            "Entry maintenance"
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          "source": "w"
        },
        {
          "kind": "other",
          "name": "English entries with topic categories using raw markup",
          "parents": [
            "Entries with topic categories using raw markup",
            "Entry maintenance"
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          "source": "w"
        },
        {
          "kind": "other",
          "name": "English oxymorons",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "English terms with non-redundant non-automated sortkeys",
          "parents": [
            "Terms with non-redundant non-automated sortkeys",
            "Entry maintenance"
          ],
          "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 entries with language name categories using raw markup",
        "English entries with topic categories using raw markup",
        "English lemmas",
        "English multiword terms",
        "English nouns",
        "English oxymorons",
        "English terms with non-redundant non-automated sortkeys",
        "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"
}