"κατ' αρχάς" meaning in Greek

{
  "etymology_templates": [
    {
      "args": {
        "1": "el",
        "2": "grc",
        "3": "-"
      },
      "expansion": "Ancient Greek",
      "name": "uder"
    }
  ],
  "etymology_text": "Ancient Greek set phrase.",
  "forms": [
    {
      "form": "kat' archás",
      "tags": [
        "romanization"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "el",
        "2": "prepositional phrase",
        "head": "κατ' αρχάς"
      },
      "expansion": "κατ' αρχάς • (kat' archás)",
      "name": "head"
    }
  ],
  "lang": "Greek",
  "lang_code": "el",
  "pos": "prep_phrase",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "Greek entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Greek undefined derivations",
          "parents": [
            "Undefined derivations",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with 1 entry",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w"
        }
      ],
      "glosses": [
        "first, first of all, at the outset, initially"
      ],
      "id": "en-κατ'_αρχάς-el-prep_phrase-moCbGvK6",
      "links": [
        [
          "first",
          "first#Adverb"
        ],
        [
          "first of all",
          "first of all"
        ],
        [
          "outset",
          "outset"
        ],
        [
          "initially",
          "initially"
        ]
      ],
      "related": [
        {
          "roman": "kat' archín",
          "word": "κατ' αρχήν"
        }
      ],
      "synonyms": [
        {
          "word": "αρχικά"
        },
        {
          "word": "αρχή"
        },
        {
          "roman": "katarchás",
          "word": "καταρχάς"
        }
      ]
    }
  ],
  "word": "κατ' αρχάς"
}

{
  "etymology_templates": [
    {
      "args": {
        "1": "el",
        "2": "grc",
        "3": "-"
      },
      "expansion": "Ancient Greek",
      "name": "uder"
    }
  ],
  "etymology_text": "Ancient Greek set phrase.",
  "forms": [
    {
      "form": "kat' archás",
      "tags": [
        "romanization"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "el",
        "2": "prepositional phrase",
        "head": "κατ' αρχάς"
      },
      "expansion": "κατ' αρχάς • (kat' archás)",
      "name": "head"
    }
  ],
  "lang": "Greek",
  "lang_code": "el",
  "pos": "prep_phrase",
  "related": [
    {
      "roman": "kat' archín",
      "word": "κατ' αρχήν"
    }
  ],
  "senses": [
    {
      "categories": [
        "Greek entries with incorrect language header",
        "Greek lemmas",
        "Greek multiword terms",
        "Greek prepositional phrases",
        "Greek terms derived from Ancient Greek",
        "Greek undefined derivations",
        "Pages with 1 entry",
        "Pages with entries"
      ],
      "glosses": [
        "first, first of all, at the outset, initially"
      ],
      "links": [
        [
          "first",
          "first#Adverb"
        ],
        [
          "first of all",
          "first of all"
        ],
        [
          "outset",
          "outset"
        ],
        [
          "initially",
          "initially"
        ]
      ],
      "synonyms": [
        {
          "word": "αρχικά"
        },
        {
          "word": "αρχή"
        }
      ]
    }
  ],
  "synonyms": [
    {
      "roman": "katarchás",
      "word": "καταρχάς"
    }
  ],
  "word": "κατ' αρχάς"
}