"caustic alkali" meaning in English

{
  "forms": [
    {
      "form": "caustic alkalis",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "~"
      },
      "expansion": "caustic alkali (countable and uncountable, plural caustic alkalis)",
      "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": "Entries with translation boxes",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Mandarin terms with redundant transliterations",
          "parents": [],
          "source": "w"
        },
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          "kind": "other",
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          "source": "w"
        },
        {
          "kind": "other",
          "langcode": "en",
          "name": "Inorganic compounds",
          "orig": "en:Inorganic compounds",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "langcode": "en",
          "name": "Potassium",
          "orig": "en:Potassium",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "langcode": "en",
          "name": "Sodium",
          "orig": "en:Sodium",
          "parents": [],
          "source": "w"
        }
      ],
      "glosses": [
        "The hydrate of potassium (called caustic potash) or sodium (caustic soda)."
      ],
      "id": "en-caustic_alkali-en-noun-ubqazU-t",
      "links": [
        [
          "inorganic chemistry",
          "inorganic chemistry"
        ],
        [
          "hydrate",
          "hydrate"
        ],
        [
          "potassium",
          "potassium"
        ],
        [
          "caustic potash",
          "caustic potash#English"
        ],
        [
          "sodium",
          "sodium"
        ],
        [
          "caustic soda",
          "caustic soda#English"
        ]
      ],
      "raw_glosses": [
        "(inorganic chemistry, dated) The hydrate of potassium (called caustic potash) or sodium (caustic soda)."
      ],
      "tags": [
        "countable",
        "dated",
        "uncountable"
      ],
      "topics": [
        "chemistry",
        "inorganic-chemistry",
        "natural-sciences",
        "physical-sciences"
      ],
      "translations": [
        {
          "code": "cmn",
          "lang": "Chinese Mandarin",
          "lang_code": "cmn",
          "roman": "kēxìngjiǎn",
          "sense": "Translations",
          "word": "苛性鹼 /苛性碱"
        }
      ]
    }
  ],
  "word": "caustic alkali"
}

{
  "forms": [
    {
      "form": "caustic alkalis",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "~"
      },
      "expansion": "caustic alkali (countable and uncountable, plural caustic alkalis)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        "English countable nouns",
        "English dated terms",
        "English entries with incorrect language header",
        "English lemmas",
        "English multiword terms",
        "English nouns",
        "English uncountable nouns",
        "Entries with translation boxes",
        "Mandarin terms with redundant transliterations",
        "Pages with 1 entry",
        "Pages with entries",
        "Terms with Mandarin translations",
        "Translation table header lacks gloss",
        "en:Inorganic compounds",
        "en:Potassium",
        "en:Sodium"
      ],
      "glosses": [
        "The hydrate of potassium (called caustic potash) or sodium (caustic soda)."
      ],
      "links": [
        [
          "inorganic chemistry",
          "inorganic chemistry"
        ],
        [
          "hydrate",
          "hydrate"
        ],
        [
          "potassium",
          "potassium"
        ],
        [
          "caustic potash",
          "caustic potash#English"
        ],
        [
          "sodium",
          "sodium"
        ],
        [
          "caustic soda",
          "caustic soda#English"
        ]
      ],
      "raw_glosses": [
        "(inorganic chemistry, dated) The hydrate of potassium (called caustic potash) or sodium (caustic soda)."
      ],
      "tags": [
        "countable",
        "dated",
        "uncountable"
      ],
      "topics": [
        "chemistry",
        "inorganic-chemistry",
        "natural-sciences",
        "physical-sciences"
      ]
    }
  ],
  "translations": [
    {
      "code": "cmn",
      "lang": "Chinese Mandarin",
      "lang_code": "cmn",
      "roman": "kēxìngjiǎn",
      "sense": "Translations",
      "word": "苛性鹼 /苛性碱"
    }
  ],
  "word": "caustic alkali"
}