"D-" meaning in Coréen

{
  "categories": [
    {
      "kind": "other",
      "name": "Mots en coréen issus d’un mot en anglais",
      "parents": [],
      "source": "w"
    },
    {
      "kind": "other",
      "name": "Préfixes en coréen",
      "parents": [],
      "source": "w"
    },
    {
      "kind": "other",
      "name": "Coréen",
      "orig": "coréen",
      "parents": [],
      "source": "w"
    }
  ],
  "etymology_texts": [
    "De l’anglais D-Day (« jour J »)."
  ],
  "forms": [
    {
      "form": "디 마이너스-",
      "raw_tags": [
        "Hangeul"
      ]
    },
    {
      "form": "디마이너스",
      "raw_tags": [
        "Prononciation"
      ]
    },
    {
      "form": "/ti.ma.i.nʌ.sɯ/",
      "raw_tags": [
        "Prononciation"
      ]
    },
    {
      "form": "[ti.ma.i.nʌ.sɯ]",
      "raw_tags": [
        "Prononciation"
      ]
    },
    {
      "form": "di maineoseu-",
      "tags": [
        "transcription"
      ]
    }
  ],
  "lang": "Coréen",
  "lang_code": "ko",
  "pos": "prefix",
  "pos_title": "Préfixe",
  "senses": [
    {
      "examples": [
        {
          "text": "오늘은 여행 D-2야.",
          "translation": "C’est 2 jours avant le voyage aujourd’hui."
        }
      ],
      "glosses": [
        "… jours avant le grand événement."
      ],
      "id": "fr-D--ko-prefix-AIzEplCN"
    }
  ],
  "tags": [
    "morpheme"
  ],
  "word": "D-"
}

{
  "categories": [
    "Mots en coréen issus d’un mot en anglais",
    "Préfixes en coréen",
    "coréen"
  ],
  "etymology_texts": [
    "De l’anglais D-Day (« jour J »)."
  ],
  "forms": [
    {
      "form": "디 마이너스-",
      "raw_tags": [
        "Hangeul"
      ]
    },
    {
      "form": "디마이너스",
      "raw_tags": [
        "Prononciation"
      ]
    },
    {
      "form": "/ti.ma.i.nʌ.sɯ/",
      "raw_tags": [
        "Prononciation"
      ]
    },
    {
      "form": "[ti.ma.i.nʌ.sɯ]",
      "raw_tags": [
        "Prononciation"
      ]
    },
    {
      "form": "di maineoseu-",
      "tags": [
        "transcription"
      ]
    }
  ],
  "lang": "Coréen",
  "lang_code": "ko",
  "pos": "prefix",
  "pos_title": "Préfixe",
  "senses": [
    {
      "examples": [
        {
          "text": "오늘은 여행 D-2야.",
          "translation": "C’est 2 jours avant le voyage aujourd’hui."
        }
      ],
      "glosses": [
        "… jours avant le grand événement."
      ]
    }
  ],
  "tags": [
    "morpheme"
  ],
  "word": "D-"
}