"aethai" meaning in Welsh

{
  "head_templates": [
    {
      "args": {},
      "expansion": "aethai",
      "name": "cy-verb form"
    }
  ],
  "lang": "Welsh",
  "lang_code": "cy",
  "pos": "verb",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "Pages with 1 entry",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Welsh entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        }
      ],
      "form_of": [
        {
          "word": "mynd"
        }
      ],
      "glosses": [
        "third-person singular pluperfect of mynd"
      ],
      "id": "en-aethai-cy-verb-LB0Ol6Tg",
      "links": [
        [
          "mynd",
          "mynd#Welsh"
        ]
      ],
      "raw_glosses": [
        "(literary) third-person singular pluperfect of mynd"
      ],
      "synonyms": [
        {
          "word": "elsai"
        }
      ],
      "tags": [
        "form-of",
        "literary",
        "pluperfect",
        "singular",
        "third-person"
      ]
    }
  ],
  "sounds": [
    {
      "ipa": "/ˈeɨ̯θai̯/",
      "tags": [
        "North-Wales"
      ]
    },
    {
      "ipa": "/ˈei̯θai̯/",
      "tags": [
        "South-Wales"
      ]
    }
  ],
  "word": "aethai"
}

{
  "head_templates": [
    {
      "args": {},
      "expansion": "aethai",
      "name": "cy-verb form"
    }
  ],
  "lang": "Welsh",
  "lang_code": "cy",
  "pos": "verb",
  "senses": [
    {
      "categories": [
        "Pages with 1 entry",
        "Pages with entries",
        "Welsh entries with incorrect language header",
        "Welsh literary terms",
        "Welsh non-lemma forms",
        "Welsh verb forms"
      ],
      "form_of": [
        {
          "word": "mynd"
        }
      ],
      "glosses": [
        "third-person singular pluperfect of mynd"
      ],
      "links": [
        [
          "mynd",
          "mynd#Welsh"
        ]
      ],
      "raw_glosses": [
        "(literary) third-person singular pluperfect of mynd"
      ],
      "tags": [
        "form-of",
        "literary",
        "pluperfect",
        "singular",
        "third-person"
      ]
    }
  ],
  "sounds": [
    {
      "ipa": "/ˈeɨ̯θai̯/",
      "tags": [
        "North-Wales"
      ]
    },
    {
      "ipa": "/ˈei̯θai̯/",
      "tags": [
        "South-Wales"
      ]
    }
  ],
  "synonyms": [
    {
      "word": "elsai"
    }
  ],
  "word": "aethai"
}