"bottom type" meaning in English

{
  "forms": [
    {
      "form": "bottom types",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "bottom type (plural bottom types)",
      "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": "Programming",
          "orig": "en:Programming",
          "parents": [
            "Computing",
            "Software engineering",
            "Technology",
            "Computer science",
            "Engineering",
            "Software",
            "All topics",
            "Sciences",
            "Applied sciences",
            "Media",
            "Fundamental",
            "Communication"
          ],
          "source": "w"
        }
      ],
      "examples": [
        {
          "ref": "2017, Toby Weston, Scala for Java Developers: A Practical Primer, Apress, page 25",
          "text": "A new notion to many Java developers will be the idea that a class hierarchy can have common bottom types. These are types that are subtypes of all types. Scala's types Null and Nothing are both bottom types.",
          "type": "quotation"
        }
      ],
      "glosses": [
        "The type that is a subtype of all other types."
      ],
      "id": "en-bottom_type-en-noun-jkR874On",
      "links": [
        [
          "type theory",
          "type theory"
        ],
        [
          "programming",
          "programming#Noun"
        ],
        [
          "type",
          "type"
        ],
        [
          "subtype",
          "subtype"
        ]
      ],
      "qualifier": "type theory",
      "raw_glosses": [
        "(type theory, programming) The type that is a subtype of all other types."
      ],
      "topics": [
        "computing",
        "engineering",
        "mathematics",
        "natural-sciences",
        "physical-sciences",
        "programming",
        "sciences"
      ]
    }
  ],
  "word": "bottom type"
}

{
  "forms": [
    {
      "form": "bottom types",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "bottom type (plural bottom types)",
      "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 terms with quotations",
        "en:Programming"
      ],
      "examples": [
        {
          "ref": "2017, Toby Weston, Scala for Java Developers: A Practical Primer, Apress, page 25",
          "text": "A new notion to many Java developers will be the idea that a class hierarchy can have common bottom types. These are types that are subtypes of all types. Scala's types Null and Nothing are both bottom types.",
          "type": "quotation"
        }
      ],
      "glosses": [
        "The type that is a subtype of all other types."
      ],
      "links": [
        [
          "type theory",
          "type theory"
        ],
        [
          "programming",
          "programming#Noun"
        ],
        [
          "type",
          "type"
        ],
        [
          "subtype",
          "subtype"
        ]
      ],
      "qualifier": "type theory",
      "raw_glosses": [
        "(type theory, programming) The type that is a subtype of all other types."
      ],
      "topics": [
        "computing",
        "engineering",
        "mathematics",
        "natural-sciences",
        "physical-sciences",
        "programming",
        "sciences"
      ]
    }
  ],
  "word": "bottom type"
}