"fos" meaning in Français

{
  "categories": [
    {
      "kind": "other",
      "name": "Abréviations en français",
      "parents": [],
      "source": "w"
    },
    {
      "kind": "other",
      "name": "Formes de noms communs en français",
      "parents": [],
      "source": "w"
    },
    {
      "kind": "other",
      "name": "Français",
      "orig": "français",
      "parents": [],
      "source": "w"
    }
  ],
  "etymology_texts": [
    "abréviation de folios."
  ],
  "forms": [
    {
      "form": "fᵒ",
      "tags": [
        "singular"
      ]
    },
    {
      "form": "fᵒˢ",
      "tags": [
        "plural"
      ]
    }
  ],
  "lang": "Français",
  "lang_code": "fr",
  "notes": [
    "La forme fᵒˢ est recommandée plutôt que la forme ff. par le Lexique des règles typographiques en usage à l’Imprimerie nationale, 2002."
  ],
  "pos": "noun",
  "pos_title": "Forme de nom commun",
  "senses": [
    {
      "form_of": [
        {
          "word": "Folios"
        }
      ],
      "glosses": [
        "Folios."
      ],
      "id": "fr-fos-fr-noun-G0~z3O8F"
    }
  ],
  "sounds": [
    {
      "ipa": "\\fɔ.ljo\\"
    }
  ],
  "synonyms": [
    {
      "word": "ff."
    }
  ],
  "tags": [
    "form-of",
    "masculine",
    "plural"
  ],
  "word": "fos"
}

{
  "categories": [
    "Abréviations en français",
    "Formes de noms communs en français",
    "français"
  ],
  "etymology_texts": [
    "abréviation de folios."
  ],
  "forms": [
    {
      "form": "fᵒ",
      "tags": [
        "singular"
      ]
    },
    {
      "form": "fᵒˢ",
      "tags": [
        "plural"
      ]
    }
  ],
  "lang": "Français",
  "lang_code": "fr",
  "notes": [
    "La forme fᵒˢ est recommandée plutôt que la forme ff. par le Lexique des règles typographiques en usage à l’Imprimerie nationale, 2002."
  ],
  "pos": "noun",
  "pos_title": "Forme de nom commun",
  "senses": [
    {
      "form_of": [
        {
          "word": "Folios"
        }
      ],
      "glosses": [
        "Folios."
      ]
    }
  ],
  "sounds": [
    {
      "ipa": "\\fɔ.ljo\\"
    }
  ],
  "synonyms": [
    {
      "word": "ff."
    }
  ],
  "tags": [
    "form-of",
    "masculine",
    "plural"
  ],
  "word": "fos"
}