"четырехлетний" meaning in Russian

{
  "forms": [
    {
      "form": "četyrjoxlétnij",
      "tags": [
        "romanization"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "noacccat": "1",
        "notrcat": "1",
        "tr": "četyrjoxlétnij"
      },
      "expansion": "четырехлетний • (četyrjoxlétnij)",
      "name": "ru-adj"
    }
  ],
  "lang": "Russian",
  "lang_code": "ru",
  "pos": "adj",
  "senses": [
    {
      "alt_of": [
        {
          "extra": "četyrjoxlétnij",
          "word": "четырёхле́тний"
        }
      ],
      "categories": [
        {
          "kind": "other",
          "name": "Pages with 1 entry",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Russian entries with incorrect language header",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Russian terms with non-redundant manual transliterations",
          "parents": [],
          "source": "w"
        }
      ],
      "glosses": [
        "alternative spelling of четырёхле́тний (četyrjoxlétnij)"
      ],
      "id": "en-четырехлетний-ru-adj-~NWc2KLW",
      "links": [
        [
          "четырёхле́тний",
          "четырёхлетний#Russian"
        ]
      ],
      "tags": [
        "alt-of",
        "alternative"
      ]
    }
  ],
  "word": "четырехлетний"
}

{
  "forms": [
    {
      "form": "četyrjoxlétnij",
      "tags": [
        "romanization"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "noacccat": "1",
        "notrcat": "1",
        "tr": "četyrjoxlétnij"
      },
      "expansion": "четырехлетний • (četyrjoxlétnij)",
      "name": "ru-adj"
    }
  ],
  "lang": "Russian",
  "lang_code": "ru",
  "pos": "adj",
  "senses": [
    {
      "alt_of": [
        {
          "extra": "četyrjoxlétnij",
          "word": "четырёхле́тний"
        }
      ],
      "categories": [
        "Pages with 1 entry",
        "Pages with entries",
        "Russian adjectives",
        "Russian entries with incorrect language header",
        "Russian lemmas",
        "Russian terms spelled with Е instead of Ё",
        "Russian terms with non-redundant manual transliterations",
        "Russian terms with redundant head parameter"
      ],
      "glosses": [
        "alternative spelling of четырёхле́тний (četyrjoxlétnij)"
      ],
      "links": [
        [
          "четырёхле́тний",
          "четырёхлетний#Russian"
        ]
      ],
      "tags": [
        "alt-of",
        "alternative"
      ]
    }
  ],
  "word": "четырехлетний"
}