"( )" meaning in Mon

{
  "head_templates": [
    {
      "args": {
        "1": "mnw",
        "2": "punctuation mark",
        "cat2": "matched pairs",
        "tr": "-"
      },
      "expansion": "( )",
      "name": "head"
    }
  ],
  "lang": "Mon",
  "lang_code": "mnw",
  "pos": "punct",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "Mon entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "topical",
          "name": "Mon matched pairs",
          "parents": [
            "Matched pairs",
            "Symbols",
            "Letters, symbols, and punctuation",
            "Orthography",
            "Writing",
            "Human behaviour",
            "Language",
            "Human",
            "Communication",
            "All topics",
            "Fundamental"
          ],
          "source": "w"
        },
        {
          "kind": "topical",
          "name": "Mon punctuation marks",
          "parents": [
            "Punctuation marks",
            "Letters, symbols, and punctuation",
            "Symbols",
            "Orthography",
            "Writing",
            "Human behaviour",
            "Language",
            "Human",
            "Communication",
            "All topics",
            "Fundamental"
          ],
          "source": "w"
        }
      ],
      "examples": [
        {
          "english": "The 68th Mon National Day",
          "text": "တ္ၚဲကောန်ဂကူမန်မရနုက်ကဵု (၆၈) ဝါ",
          "type": "example"
        }
      ],
      "glosses": [
        "sometimes used to enclose digits to distinguish from letters"
      ],
      "id": "en-(_)-mnw-punct-Y-MIHQkK",
      "raw_tags": [
        "punctuation"
      ]
    }
  ],
  "word": "( )"
}

{
  "head_templates": [
    {
      "args": {
        "1": "mnw",
        "2": "punctuation mark",
        "cat2": "matched pairs",
        "tr": "-"
      },
      "expansion": "( )",
      "name": "head"
    }
  ],
  "lang": "Mon",
  "lang_code": "mnw",
  "pos": "punct",
  "senses": [
    {
      "categories": [
        "Mon entries with incorrect language header",
        "Mon lemmas",
        "Mon matched pairs",
        "Mon punctuation marks",
        "Mon terms with usage examples"
      ],
      "examples": [
        {
          "english": "The 68th Mon National Day",
          "text": "တ္ၚဲကောန်ဂကူမန်မရနုက်ကဵု (၆၈) ဝါ",
          "type": "example"
        }
      ],
      "glosses": [
        "sometimes used to enclose digits to distinguish from letters"
      ],
      "raw_tags": [
        "punctuation"
      ]
    }
  ],
  "word": "( )"
}