"retrois" meaning in Ancien français

{
  "categories": [
    {
      "kind": "other",
      "name": "Noms communs en ancien français",
      "parents": [],
      "source": "w"
    },
    {
      "kind": "other",
      "name": "Ancien français",
      "orig": "ancien français",
      "parents": [],
      "source": "w"
    }
  ],
  "forms": [
    {
      "form": "retros"
    },
    {
      "form": "retrous"
    }
  ],
  "lang": "Ancien français",
  "lang_code": "fro",
  "pos": "noun",
  "pos_title": "Nom commun",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "Exemples en ancien français",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Exemples en ancien français à traduire",
          "parents": [],
          "source": "w"
        }
      ],
      "examples": [
        {
          "bold_text_offsets": [
            [
              19,
              26
            ]
          ],
          "ref": "Le Roman de Thèbes, édition deConstans, p. 391, tome I",
          "text": "En sa main tint un retrois brief"
        },
        {
          "bold_text_offsets": [
            [
              5,
              11
            ]
          ],
          "ref": "Le Roman de Troie, édition deConstans, tome II, p. 72, c. 1165",
          "text": "D’un retros fiert en mi le vis"
        }
      ],
      "glosses": [
        "Éclat, morceau."
      ],
      "id": "fr-retrois-fro-noun-g25NUiMD"
    }
  ],
  "tags": [
    "masculine"
  ],
  "word": "retrois"
}

{
  "categories": [
    "Noms communs en ancien français",
    "ancien français"
  ],
  "forms": [
    {
      "form": "retros"
    },
    {
      "form": "retrous"
    }
  ],
  "lang": "Ancien français",
  "lang_code": "fro",
  "pos": "noun",
  "pos_title": "Nom commun",
  "senses": [
    {
      "categories": [
        "Exemples en ancien français",
        "Exemples en ancien français à traduire"
      ],
      "examples": [
        {
          "bold_text_offsets": [
            [
              19,
              26
            ]
          ],
          "ref": "Le Roman de Thèbes, édition deConstans, p. 391, tome I",
          "text": "En sa main tint un retrois brief"
        },
        {
          "bold_text_offsets": [
            [
              5,
              11
            ]
          ],
          "ref": "Le Roman de Troie, édition deConstans, tome II, p. 72, c. 1165",
          "text": "D’un retros fiert en mi le vis"
        }
      ],
      "glosses": [
        "Éclat, morceau."
      ]
    }
  ],
  "tags": [
    "masculine"
  ],
  "word": "retrois"
}