"Bell number" meaning in English

{
  "etymology_text": "Named after Eric Temple Bell, who wrote about them in the 1930s.",
  "forms": [
    {
      "form": "Bell numbers",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "Bell number (plural Bell numbers)",
      "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": "English entries with language name categories using raw markup",
          "parents": [
            "Entries with language name categories using raw markup",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "English terms with non-redundant non-automated sortkeys",
          "parents": [
            "Terms with non-redundant non-automated sortkeys",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "topical",
          "langcode": "en",
          "name": "Combinatorics",
          "orig": "en:Combinatorics",
          "parents": [
            "Mathematics",
            "Formal sciences",
            "Sciences",
            "All topics",
            "Fundamental"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "Any member of a sequence of numbers that count the possible partitions of a set, such that the nth number Bₙ is the number of different ways to partition a set that has exactly n elements."
      ],
      "id": "en-Bell_number-en-noun-PhGz6uAK",
      "links": [
        [
          "combinatorics",
          "combinatorics"
        ],
        [
          "partition",
          "partition"
        ],
        [
          "set",
          "set"
        ],
        [
          "element",
          "element"
        ]
      ],
      "raw_glosses": [
        "(combinatorics) Any member of a sequence of numbers that count the possible partitions of a set, such that the nth number Bₙ is the number of different ways to partition a set that has exactly n elements."
      ],
      "topics": [
        "combinatorics",
        "mathematics",
        "sciences"
      ],
      "wikipedia": [
        "Bell number"
      ]
    }
  ],
  "word": "Bell number"
}

{
  "etymology_text": "Named after Eric Temple Bell, who wrote about them in the 1930s.",
  "forms": [
    {
      "form": "Bell numbers",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "Bell number (plural Bell numbers)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        "English countable nouns",
        "English entries with incorrect language header",
        "English entries with language name categories using raw markup",
        "English eponyms",
        "English lemmas",
        "English multiword terms",
        "English nouns",
        "English terms with non-redundant non-automated sortkeys",
        "en:Combinatorics"
      ],
      "glosses": [
        "Any member of a sequence of numbers that count the possible partitions of a set, such that the nth number Bₙ is the number of different ways to partition a set that has exactly n elements."
      ],
      "links": [
        [
          "combinatorics",
          "combinatorics"
        ],
        [
          "partition",
          "partition"
        ],
        [
          "set",
          "set"
        ],
        [
          "element",
          "element"
        ]
      ],
      "raw_glosses": [
        "(combinatorics) Any member of a sequence of numbers that count the possible partitions of a set, such that the nth number Bₙ is the number of different ways to partition a set that has exactly n elements."
      ],
      "topics": [
        "combinatorics",
        "mathematics",
        "sciences"
      ],
      "wikipedia": [
        "Bell number"
      ]
    }
  ],
  "word": "Bell number"
}