"motion detector" meaning in English

{
  "forms": [
    {
      "form": "motion detectors",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "motion detector (plural motion detectors)",
      "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": "Mandarin terms with non-redundant manual transliterations",
          "parents": [
            "Terms with non-redundant manual transliterations",
            "Entry maintenance"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "A device used in security systems that can alert the user of the presence of a moving object."
      ],
      "id": "en-motion_detector-en-noun-fNQ0P7-Q",
      "translations": [
        {
          "code": "cmn",
          "lang": "Chinese Mandarin",
          "sense": "device used in security systems",
          "word": "動作感應器"
        },
        {
          "code": "cmn",
          "lang": "Chinese Mandarin",
          "roman": "dòngzuò gǎnyīngqì",
          "sense": "device used in security systems",
          "word": "动作感应器"
        },
        {
          "code": "fi",
          "lang": "Finnish",
          "sense": "device used in security systems",
          "word": "liiketunnistin"
        },
        {
          "code": "de",
          "lang": "German",
          "sense": "device used in security systems",
          "tags": [
            "neuter"
          ],
          "word": "Bewegungsmelder"
        },
        {
          "code": "hu",
          "lang": "Hungarian",
          "sense": "device used in security systems",
          "word": "mozgásérzékelő"
        },
        {
          "code": "ga",
          "lang": "Irish",
          "sense": "device used in security systems",
          "tags": [
            "masculine"
          ],
          "word": "brathadóir gluaiseachta"
        },
        {
          "code": "it",
          "lang": "Italian",
          "sense": "device used in security systems",
          "tags": [
            "masculine"
          ],
          "word": "sensore di movimento"
        },
        {
          "code": "ru",
          "lang": "Russian",
          "roman": "detéktor dvižénija",
          "sense": "device used in security systems",
          "tags": [
            "masculine"
          ],
          "word": "дете́ктор движе́ния"
        }
      ],
      "wikipedia": [
        "motion detector"
      ]
    }
  ],
  "word": "motion detector"
}

{
  "forms": [
    {
      "form": "motion detectors",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "motion detector (plural motion detectors)",
      "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",
        "Mandarin terms with non-redundant manual transliterations"
      ],
      "glosses": [
        "A device used in security systems that can alert the user of the presence of a moving object."
      ],
      "wikipedia": [
        "motion detector"
      ]
    }
  ],
  "translations": [
    {
      "code": "cmn",
      "lang": "Chinese Mandarin",
      "sense": "device used in security systems",
      "word": "動作感應器"
    },
    {
      "code": "cmn",
      "lang": "Chinese Mandarin",
      "roman": "dòngzuò gǎnyīngqì",
      "sense": "device used in security systems",
      "word": "动作感应器"
    },
    {
      "code": "fi",
      "lang": "Finnish",
      "sense": "device used in security systems",
      "word": "liiketunnistin"
    },
    {
      "code": "de",
      "lang": "German",
      "sense": "device used in security systems",
      "tags": [
        "neuter"
      ],
      "word": "Bewegungsmelder"
    },
    {
      "code": "hu",
      "lang": "Hungarian",
      "sense": "device used in security systems",
      "word": "mozgásérzékelő"
    },
    {
      "code": "ga",
      "lang": "Irish",
      "sense": "device used in security systems",
      "tags": [
        "masculine"
      ],
      "word": "brathadóir gluaiseachta"
    },
    {
      "code": "it",
      "lang": "Italian",
      "sense": "device used in security systems",
      "tags": [
        "masculine"
      ],
      "word": "sensore di movimento"
    },
    {
      "code": "ru",
      "lang": "Russian",
      "roman": "detéktor dvižénija",
      "sense": "device used in security systems",
      "tags": [
        "masculine"
      ],
      "word": "дете́ктор движе́ния"
    }
  ],
  "word": "motion detector"
}