"dū" meaning in Proto-Celtic

{
  "descendants": [
    {
      "depth": 1,
      "templates": [
        {
          "args": {
            "1": "cel-bry-pro",
            "2": "*di"
          },
          "expansion": "Proto-Brythonic: *di\nBreton: da\nCornish: dhe\nOld Welsh: di\nMiddle Welsh: y (“to, for”)\nWelsh: i (“to, for”)",
          "name": "desctree"
        }
      ],
      "text": "Proto-Brythonic: *di\nBreton: da\nCornish: dhe\nOld Welsh: di\nMiddle Welsh: y (“to, for”)\nWelsh: i (“to, for”)"
    },
    {
      "depth": 1,
      "templates": [
        {
          "args": {
            "1": "sga",
            "2": "do"
          },
          "expansion": "Old Irish: do",
          "name": "desc"
        }
      ],
      "text": "Old Irish: do"
    },
    {
      "depth": 2,
      "templates": [
        {
          "args": {
            "1": "ga",
            "2": "do"
          },
          "expansion": "Irish: do",
          "name": "desc"
        }
      ],
      "text": "Irish: do"
    },
    {
      "depth": 2,
      "templates": [
        {
          "args": {
            "1": "gd",
            "2": "do"
          },
          "expansion": "Scottish Gaelic: do",
          "name": "desc"
        }
      ],
      "text": "Scottish Gaelic: do"
    }
  ],
  "etymology_templates": [
    {
      "args": {
        "1": "cel-pro",
        "2": "ine-pro",
        "3": "*de",
        "4": "*de, *do"
      },
      "expansion": "Proto-Indo-European *de, *do",
      "name": "der"
    }
  ],
  "etymology_text": "From Proto-Indo-European *de, *do.",
  "head_templates": [
    {
      "args": {
        "1": "cel-pro",
        "2": "preposition"
      },
      "expansion": "*dū",
      "name": "head"
    }
  ],
  "lang": "Proto-Celtic",
  "lang_code": "cel-pro",
  "original_title": "Reconstruction:Proto-Celtic/dū",
  "pos": "prep",
  "senses": [
    {
      "categories": [
        {
          "_dis": "100 0",
          "kind": "other",
          "name": "Proto-Celtic entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w+disamb"
        },
        {
          "_dis": "79 21",
          "kind": "other",
          "name": "Proto-Celtic prepositions",
          "parents": [],
          "source": "w+disamb"
        }
      ],
      "glosses": [
        "to, towards"
      ],
      "id": "en-dū-cel-pro-prep-8Z5Bjywf",
      "links": [
        [
          "to",
          "to"
        ],
        [
          "towards",
          "towards"
        ]
      ],
      "tags": [
        "reconstruction"
      ]
    },
    {
      "glosses": [
        "for"
      ],
      "id": "en-dū-cel-pro-prep-EMIrz0x2",
      "links": [
        [
          "for",
          "for"
        ]
      ],
      "tags": [
        "reconstruction"
      ]
    }
  ],
  "synonyms": [
    {
      "_dis1": "0 0",
      "word": "do"
    }
  ],
  "wikipedia": [
    "Brill Publishers"
  ],
  "word": "dū"
}

{
  "categories": [
    "Proto-Celtic entries with incorrect language header",
    "Proto-Celtic lemmas",
    "Proto-Celtic prepositions",
    "Proto-Celtic terms derived from Proto-Indo-European"
  ],
  "descendants": [
    {
      "depth": 1,
      "templates": [
        {
          "args": {
            "1": "cel-bry-pro",
            "2": "*di"
          },
          "expansion": "Proto-Brythonic: *di\nBreton: da\nCornish: dhe\nOld Welsh: di\nMiddle Welsh: y (“to, for”)\nWelsh: i (“to, for”)",
          "name": "desctree"
        }
      ],
      "text": "Proto-Brythonic: *di\nBreton: da\nCornish: dhe\nOld Welsh: di\nMiddle Welsh: y (“to, for”)\nWelsh: i (“to, for”)"
    },
    {
      "depth": 1,
      "templates": [
        {
          "args": {
            "1": "sga",
            "2": "do"
          },
          "expansion": "Old Irish: do",
          "name": "desc"
        }
      ],
      "text": "Old Irish: do"
    },
    {
      "depth": 2,
      "templates": [
        {
          "args": {
            "1": "ga",
            "2": "do"
          },
          "expansion": "Irish: do",
          "name": "desc"
        }
      ],
      "text": "Irish: do"
    },
    {
      "depth": 2,
      "templates": [
        {
          "args": {
            "1": "gd",
            "2": "do"
          },
          "expansion": "Scottish Gaelic: do",
          "name": "desc"
        }
      ],
      "text": "Scottish Gaelic: do"
    }
  ],
  "etymology_templates": [
    {
      "args": {
        "1": "cel-pro",
        "2": "ine-pro",
        "3": "*de",
        "4": "*de, *do"
      },
      "expansion": "Proto-Indo-European *de, *do",
      "name": "der"
    }
  ],
  "etymology_text": "From Proto-Indo-European *de, *do.",
  "head_templates": [
    {
      "args": {
        "1": "cel-pro",
        "2": "preposition"
      },
      "expansion": "*dū",
      "name": "head"
    }
  ],
  "lang": "Proto-Celtic",
  "lang_code": "cel-pro",
  "original_title": "Reconstruction:Proto-Celtic/dū",
  "pos": "prep",
  "senses": [
    {
      "glosses": [
        "to, towards"
      ],
      "links": [
        [
          "to",
          "to"
        ],
        [
          "towards",
          "towards"
        ]
      ],
      "tags": [
        "reconstruction"
      ]
    },
    {
      "glosses": [
        "for"
      ],
      "links": [
        [
          "for",
          "for"
        ]
      ],
      "tags": [
        "reconstruction"
      ]
    }
  ],
  "synonyms": [
    {
      "word": "do"
    }
  ],
  "wikipedia": [
    "Brill Publishers"
  ],
  "word": "dū"
}