"jack post" meaning in English

{
  "forms": [
    {
      "form": "jack posts",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "jack post (plural jack posts)",
      "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"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with 1 entry",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "topical",
          "langcode": "en",
          "name": "Construction",
          "orig": "en:Construction",
          "parents": [
            "Architecture",
            "Engineering",
            "Applied sciences",
            "Art",
            "Technology",
            "Sciences",
            "Culture",
            "All topics",
            "Society",
            "Fundamental"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "A telescoping steel post used for the temporary support of ceilings, walls, and trenches."
      ],
      "id": "en-jack_post-en-noun-Qbw8jx99",
      "links": [
        [
          "construction",
          "construction"
        ]
      ],
      "raw_glosses": [
        "(construction) A telescoping steel post used for the temporary support of ceilings, walls, and trenches."
      ],
      "topics": [
        "business",
        "construction",
        "manufacturing"
      ]
    }
  ],
  "word": "jack post"
}

{
  "forms": [
    {
      "form": "jack posts",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "jack post (plural jack posts)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        "English countable nouns",
        "English entries with incorrect language header",
        "English lemmas",
        "English multiword terms",
        "English nouns",
        "Pages with 1 entry",
        "en:Construction"
      ],
      "glosses": [
        "A telescoping steel post used for the temporary support of ceilings, walls, and trenches."
      ],
      "links": [
        [
          "construction",
          "construction"
        ]
      ],
      "raw_glosses": [
        "(construction) A telescoping steel post used for the temporary support of ceilings, walls, and trenches."
      ],
      "topics": [
        "business",
        "construction",
        "manufacturing"
      ]
    }
  ],
  "word": "jack post"
}