"fly powder" meaning in English

{
  "forms": [
    {
      "form": "fly powders",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "-",
        "2": "s"
      },
      "expansion": "fly powder (usually uncountable, plural fly powders)",
      "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"
        }
      ],
      "glosses": [
        "A poisonous powder used as an insecticide against flies."
      ],
      "id": "en-fly_powder-en-noun-8Oku-TQd",
      "links": [
        [
          "poisonous",
          "poisonous"
        ],
        [
          "insecticide",
          "insecticide"
        ]
      ],
      "tags": [
        "uncountable",
        "usually"
      ]
    }
  ],
  "sounds": [
    {
      "rhymes": "-aʊdə(ɹ)"
    }
  ],
  "word": "fly powder"
}

{
  "forms": [
    {
      "form": "fly powders",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "-",
        "2": "s"
      },
      "expansion": "fly powder (usually uncountable, plural fly powders)",
      "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 uncountable nouns",
        "Rhymes:English/aʊdə(ɹ)",
        "Rhymes:English/aʊdə(ɹ)/3 syllables"
      ],
      "glosses": [
        "A poisonous powder used as an insecticide against flies."
      ],
      "links": [
        [
          "poisonous",
          "poisonous"
        ],
        [
          "insecticide",
          "insecticide"
        ]
      ],
      "tags": [
        "uncountable",
        "usually"
      ]
    }
  ],
  "sounds": [
    {
      "rhymes": "-aʊdə(ɹ)"
    }
  ],
  "word": "fly powder"
}