"leading rein" meaning in English

{
  "forms": [
    {
      "form": "leading reins",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "leading rein (plural leading reins)",
      "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": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w"
        }
      ],
      "examples": [
        {
          "ref": "1928, Siegfried Sassoon, Memoirs of a Fox-Hunting Man, Penguin, published 2013, page 11:",
          "text": "By that time I was going for rides of six or seven miles with Dixon, and the ‘leading-rein’ was a thing of the past.",
          "type": "quote"
        }
      ],
      "glosses": [
        "A rein used to lead an animal (especially a horse) when there is no rider, or when the rider is young or inexperienced."
      ],
      "id": "en-leading_rein-en-noun-y8MUifLK",
      "links": [
        [
          "rein",
          "rein"
        ]
      ]
    }
  ],
  "word": "leading rein"
}

{
  "forms": [
    {
      "form": "leading reins",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "leading rein (plural leading reins)",
      "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",
        "English terms with quotations",
        "Pages with 1 entry",
        "Pages with entries",
        "Quotation templates to be cleaned"
      ],
      "examples": [
        {
          "ref": "1928, Siegfried Sassoon, Memoirs of a Fox-Hunting Man, Penguin, published 2013, page 11:",
          "text": "By that time I was going for rides of six or seven miles with Dixon, and the ‘leading-rein’ was a thing of the past.",
          "type": "quote"
        }
      ],
      "glosses": [
        "A rein used to lead an animal (especially a horse) when there is no rider, or when the rider is young or inexperienced."
      ],
      "links": [
        [
          "rein",
          "rein"
        ]
      ]
    }
  ],
  "word": "leading rein"
}