"work horse" meaning in English

{
  "forms": [
    {
      "form": "work horses",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "work horse (plural work horses)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "alt_of": [
        {
          "word": "workhorse"
        }
      ],
      "categories": [
        {
          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with 1 entry",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w"
        }
      ],
      "examples": [
        {
          "ref": "1956 November 8, Alexander R. Hammer, “Duplicator Still The ‘Work Horse’”, in The New York Times, →ISSN:",
          "text": "The old “work horse” of the office, the mimeograph, was a starred performer at the National Business Show, which was recently held at the New York Coliseum.",
          "type": "quote"
        }
      ],
      "glosses": [
        "Alternative form of workhorse"
      ],
      "id": "en-work_horse-en-noun-1mi0mGkn",
      "links": [
        [
          "workhorse",
          "workhorse#English"
        ]
      ],
      "tags": [
        "alt-of",
        "alternative"
      ]
    }
  ],
  "word": "work horse"
}

{
  "forms": [
    {
      "form": "work horses",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "work horse (plural work horses)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "alt_of": [
        {
          "word": "workhorse"
        }
      ],
      "categories": [
        "English countable nouns",
        "English entries with incorrect language header",
        "English lemmas",
        "English multiword terms",
        "English nouns",
        "English terms with quotations",
        "Pages with 1 entry",
        "Pages with entries"
      ],
      "examples": [
        {
          "ref": "1956 November 8, Alexander R. Hammer, “Duplicator Still The ‘Work Horse’”, in The New York Times, →ISSN:",
          "text": "The old “work horse” of the office, the mimeograph, was a starred performer at the National Business Show, which was recently held at the New York Coliseum.",
          "type": "quote"
        }
      ],
      "glosses": [
        "Alternative form of workhorse"
      ],
      "links": [
        [
          "workhorse",
          "workhorse#English"
        ]
      ],
      "tags": [
        "alt-of",
        "alternative"
      ]
    }
  ],
  "word": "work horse"
}