"triple witching" meaning in English

{
  "etymology_text": "The idea of witching for these days is from the unusual patterns of trading that can occur ahead of the contract expiries.",
  "head_templates": [
    {
      "args": {
        "1": "-"
      },
      "expansion": "triple witching (uncountable)",
      "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": "topical",
          "langcode": "en",
          "name": "Finance",
          "orig": "en:Finance",
          "parents": [
            "Business",
            "Economics",
            "Society",
            "Social sciences",
            "All topics",
            "Sciences",
            "Fundamental"
          ],
          "source": "w"
        }
      ],
      "derived": [
        {
          "word": "triple witching hour"
        }
      ],
      "glosses": [
        "Simultaneous expiry on US markets of stock index futures, stock index options, and stock options, which took place on the third Friday of March, June, September, and December. (With the introduction of single stock futures those days are now quadruple witching.)"
      ],
      "id": "en-triple_witching-en-noun-MTerLqnw",
      "links": [
        [
          "finance",
          "finance#Noun"
        ],
        [
          "quadruple witching",
          "quadruple witching"
        ]
      ],
      "raw_glosses": [
        "(finance) Simultaneous expiry on US markets of stock index futures, stock index options, and stock options, which took place on the third Friday of March, June, September, and December. (With the introduction of single stock futures those days are now quadruple witching.)"
      ],
      "tags": [
        "uncountable"
      ],
      "topics": [
        "business",
        "finance"
      ]
    }
  ],
  "word": "triple witching"
}

{
  "derived": [
    {
      "word": "triple witching hour"
    }
  ],
  "etymology_text": "The idea of witching for these days is from the unusual patterns of trading that can occur ahead of the contract expiries.",
  "head_templates": [
    {
      "args": {
        "1": "-"
      },
      "expansion": "triple witching (uncountable)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        "English entries with incorrect language header",
        "English lemmas",
        "English multiword terms",
        "English nouns",
        "English uncountable nouns",
        "en:Finance"
      ],
      "glosses": [
        "Simultaneous expiry on US markets of stock index futures, stock index options, and stock options, which took place on the third Friday of March, June, September, and December. (With the introduction of single stock futures those days are now quadruple witching.)"
      ],
      "links": [
        [
          "finance",
          "finance#Noun"
        ],
        [
          "quadruple witching",
          "quadruple witching"
        ]
      ],
      "raw_glosses": [
        "(finance) Simultaneous expiry on US markets of stock index futures, stock index options, and stock options, which took place on the third Friday of March, June, September, and December. (With the introduction of single stock futures those days are now quadruple witching.)"
      ],
      "tags": [
        "uncountable"
      ],
      "topics": [
        "business",
        "finance"
      ]
    }
  ],
  "word": "triple witching"
}