"æra" meaning in English

{
  "forms": [
    {
      "form": "æras",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "æra (plural æras)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "alt_of": [
        {
          "word": "era"
        }
      ],
      "categories": [
        {
          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        }
      ],
      "examples": [
        {
          "ref": "1798, Pierre Simon La Place, “Exposition du Système du Monde [On the System of the World]”, in The Monthly Review, new and improved, page 500",
          "text": "It is desirable that all people should adopt one and the same æra, independant of moral revolutions, and founded solely on astronomical phænomena.",
          "type": "quotation"
        },
        {
          "ref": "1892, Thomas Keightley, Fairy Mythology, London: George Bell and Sons, page 5",
          "text": "In the fourth century of our æra we find this word made plural, and even feminine, and used as the equivalent of Parcæ.",
          "type": "quotation"
        }
      ],
      "glosses": [
        "Archaic spelling of era."
      ],
      "id": "en-æra-en-noun-O0Yc-kfZ",
      "links": [
        [
          "era",
          "era#English"
        ]
      ],
      "tags": [
        "alt-of",
        "archaic"
      ]
    }
  ],
  "word": "æra"
}

{
  "forms": [
    {
      "form": "æras",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "æra (plural æras)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "alt_of": [
        {
          "word": "era"
        }
      ],
      "categories": [
        "English archaic forms",
        "English countable nouns",
        "English entries with incorrect language header",
        "English lemmas",
        "English nouns",
        "English terms spelled with Æ",
        "English terms with quotations"
      ],
      "examples": [
        {
          "ref": "1798, Pierre Simon La Place, “Exposition du Système du Monde [On the System of the World]”, in The Monthly Review, new and improved, page 500",
          "text": "It is desirable that all people should adopt one and the same æra, independant of moral revolutions, and founded solely on astronomical phænomena.",
          "type": "quotation"
        },
        {
          "ref": "1892, Thomas Keightley, Fairy Mythology, London: George Bell and Sons, page 5",
          "text": "In the fourth century of our æra we find this word made plural, and even feminine, and used as the equivalent of Parcæ.",
          "type": "quotation"
        }
      ],
      "glosses": [
        "Archaic spelling of era."
      ],
      "links": [
        [
          "era",
          "era#English"
        ]
      ],
      "tags": [
        "alt-of",
        "archaic"
      ]
    }
  ],
  "word": "æra"
}