"day job" meaning in English

{
  "etymology_templates": [
    {
      "args": {
        "1": "en",
        "2": "day",
        "3": "job"
      },
      "expansion": "day + job",
      "name": "compound"
    }
  ],
  "etymology_text": "day + job",
  "forms": [
    {
      "form": "day jobs",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "day job (plural day jobs)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "English endocentric compounds",
          "parents": [
            "Endocentric compounds",
            "Compound terms",
            "Terms by etymology"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "English entries with language name categories using raw markup",
          "parents": [
            "Entries with language name categories using raw markup",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "English terms with non-redundant non-automated sortkeys",
          "parents": [
            "Terms with non-redundant non-automated sortkeys",
            "Entry maintenance"
          ],
          "source": "w"
        }
      ],
      "derived": [
        {
          "word": "don't give up your day job"
        }
      ],
      "glosses": [
        "One's principal job; one's regular means of income."
      ],
      "id": "en-day_job-en-noun-Pgw-rqnG",
      "links": [
        [
          "principal",
          "principal"
        ],
        [
          "means",
          "means"
        ],
        [
          "income",
          "income"
        ]
      ],
      "related": [
        {
          "word": "9 to 5"
        },
        {
          "word": "moonlighting"
        }
      ],
      "synonyms": [
        {
          "word": "dayjob"
        }
      ]
    }
  ],
  "word": "day job"
}

{
  "derived": [
    {
      "word": "don't give up your day job"
    }
  ],
  "etymology_templates": [
    {
      "args": {
        "1": "en",
        "2": "day",
        "3": "job"
      },
      "expansion": "day + job",
      "name": "compound"
    }
  ],
  "etymology_text": "day + job",
  "forms": [
    {
      "form": "day jobs",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "day job (plural day jobs)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "related": [
    {
      "word": "9 to 5"
    },
    {
      "word": "moonlighting"
    }
  ],
  "senses": [
    {
      "categories": [
        "English compound terms",
        "English countable nouns",
        "English endocentric compounds",
        "English entries with incorrect language header",
        "English entries with language name categories using raw markup",
        "English lemmas",
        "English multiword terms",
        "English nouns",
        "English terms with non-redundant non-automated sortkeys"
      ],
      "glosses": [
        "One's principal job; one's regular means of income."
      ],
      "links": [
        [
          "principal",
          "principal"
        ],
        [
          "means",
          "means"
        ],
        [
          "income",
          "income"
        ]
      ]
    }
  ],
  "synonyms": [
    {
      "word": "dayjob"
    }
  ],
  "word": "day job"
}