"formation rule" meaning in English

{
  "forms": [
    {
      "form": "formation rules",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "formation rule (plural formation rules)",
      "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": "Pages with 1 entry",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "langcode": "en",
          "name": "Logic",
          "orig": "en:Logic",
          "parents": [],
          "source": "w"
        }
      ],
      "glosses": [
        "Any of a set of rules used to construct well-formed formulas of a formal language."
      ],
      "holonyms": [
        {
          "word": "formal grammar"
        },
        {
          "word": "formal language"
        }
      ],
      "id": "en-formation_rule-en-noun-cIusFpC7",
      "links": [
        [
          "logic",
          "logic"
        ],
        [
          "well-formed formula",
          "well-formed formula"
        ],
        [
          "formal language",
          "formal language"
        ]
      ],
      "raw_glosses": [
        "(logic) Any of a set of rules used to construct well-formed formulas of a formal language."
      ],
      "topics": [
        "human-sciences",
        "logic",
        "mathematics",
        "philosophy",
        "sciences"
      ]
    }
  ],
  "word": "formation rule"
}

{
  "forms": [
    {
      "form": "formation rules",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "formation rule (plural formation rules)",
      "name": "en-noun"
    }
  ],
  "holonyms": [
    {
      "word": "formal grammar"
    },
    {
      "word": "formal language"
    }
  ],
  "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",
        "Pages with 1 entry",
        "Pages with entries",
        "en:Logic"
      ],
      "glosses": [
        "Any of a set of rules used to construct well-formed formulas of a formal language."
      ],
      "links": [
        [
          "logic",
          "logic"
        ],
        [
          "well-formed formula",
          "well-formed formula"
        ],
        [
          "formal language",
          "formal language"
        ]
      ],
      "raw_glosses": [
        "(logic) Any of a set of rules used to construct well-formed formulas of a formal language."
      ],
      "topics": [
        "human-sciences",
        "logic",
        "mathematics",
        "philosophy",
        "sciences"
      ]
    }
  ],
  "word": "formation rule"
}