"ladies' night" meaning in English

{
  "forms": [
    {
      "form": "ladies' nights",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "ladies' night (plural ladies' nights)",
      "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"
        },
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          "name": "Entries with translation boxes",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with 1 entry",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with entries",
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          "source": "w"
        },
        {
          "kind": "other",
          "name": "Terms with Finnish translations",
          "parents": [],
          "source": "w"
        }
      ],
      "glosses": [
        "A night in which women are given free admission into a venue. Also called \"ladies' day\" if held during daytime."
      ],
      "id": "en-ladies'_night-en-noun-tWShKHOy",
      "related": [
        {
          "word": "girls' night out"
        }
      ],
      "translations": [
        {
          "code": "fi",
          "lang": "Finnish",
          "sense": "Translations",
          "word": "naisten ilta"
        }
      ]
    }
  ],
  "word": "ladies' night"
}

{
  "forms": [
    {
      "form": "ladies' nights",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "ladies' night (plural ladies' nights)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "related": [
    {
      "word": "girls' night out"
    }
  ],
  "senses": [
    {
      "categories": [
        "English countable nouns",
        "English entries with incorrect language header",
        "English lemmas",
        "English multiword terms",
        "English nouns",
        "Entries with translation boxes",
        "Pages with 1 entry",
        "Pages with entries",
        "Terms with Finnish translations",
        "Translation table header lacks gloss"
      ],
      "glosses": [
        "A night in which women are given free admission into a venue. Also called \"ladies' day\" if held during daytime."
      ]
    }
  ],
  "translations": [
    {
      "code": "fi",
      "lang": "Finnish",
      "sense": "Translations",
      "word": "naisten ilta"
    }
  ],
  "word": "ladies' night"
}