"shiftage" meaning in English

{
  "etymology_templates": [
    {
      "args": {
        "1": "en",
        "2": "shift",
        "3": "age"
      },
      "expansion": "shift + -age",
      "name": "suffix"
    }
  ],
  "etymology_text": "From shift + -age.",
  "head_templates": [
    {
      "args": {
        "1": "-"
      },
      "expansion": "shiftage (uncountable)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
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          "source": "w"
        },
        {
          "kind": "other",
          "name": "English terms suffixed with -age",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with 1 entry",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
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          "parents": [],
          "source": "w"
        }
      ],
      "examples": [
        {
          "ref": "1915, Jack London, The Little Lady of the Big House:",
          "text": "[…] the need to perceive and to act, to see and know, to be sure and quick, to adjust instantly to all instant shiftage of the balance of forces that bear upon the living.",
          "type": "quote"
        }
      ],
      "glosses": [
        "Movement by shifting."
      ],
      "id": "en-shiftage-en-noun-EtZbzH2w",
      "tags": [
        "uncountable"
      ]
    }
  ],
  "word": "shiftage"
}

{
  "etymology_templates": [
    {
      "args": {
        "1": "en",
        "2": "shift",
        "3": "age"
      },
      "expansion": "shift + -age",
      "name": "suffix"
    }
  ],
  "etymology_text": "From shift + -age.",
  "head_templates": [
    {
      "args": {
        "1": "-"
      },
      "expansion": "shiftage (uncountable)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        "English entries with incorrect language header",
        "English lemmas",
        "English nouns",
        "English terms suffixed with -age",
        "English terms with quotations",
        "English uncountable nouns",
        "Pages with 1 entry",
        "Pages with entries",
        "Quotation templates to be cleaned"
      ],
      "examples": [
        {
          "ref": "1915, Jack London, The Little Lady of the Big House:",
          "text": "[…] the need to perceive and to act, to see and know, to be sure and quick, to adjust instantly to all instant shiftage of the balance of forces that bear upon the living.",
          "type": "quote"
        }
      ],
      "glosses": [
        "Movement by shifting."
      ],
      "tags": [
        "uncountable"
      ]
    }
  ],
  "word": "shiftage"
}