"ff" meaning in Dutch

{
  "etymology_number": 1,
  "etymology_templates": [
    {
      "args": {
        "1": "nl",
        "2": "la",
        "3": "folio",
        "4": "",
        "5": "on the (next) page"
      },
      "expansion": "Latin folio (“on the (next) page”)",
      "name": "der"
    }
  ],
  "etymology_text": "Abbreviation of Latin folio (“on the (next) page”), ablative of folium (“leaf, page”).",
  "head_templates": [
    {
      "args": {
        "1": "nl",
        "2": "phrase"
      },
      "expansion": "ff",
      "name": "head"
    }
  ],
  "lang": "Dutch",
  "lang_code": "nl",
  "pos": "phrase",
  "senses": [
    {
      "categories": [
        {
          "_dis": "0 10 20 27 3 15 25",
          "kind": "other",
          "name": "Pages with 4 entries",
          "parents": [],
          "source": "w+disamb"
        },
        {
          "_dis": "10 90",
          "kind": "other",
          "name": "Dutch entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w+disamb"
        }
      ],
      "glosses": [
        "ff."
      ],
      "id": "en-ff-nl-phrase-YJt2yvmR",
      "links": [
        [
          "ff.",
          "ff.#English"
        ]
      ]
    }
  ],
  "word": "ff"
}

{
  "etymology_number": 2,
  "etymology_text": "When pronounced as the plural of 'f', it sounds like the Dutch word effen.",
  "head_templates": [
    {
      "args": {
        "1": "nl",
        "2": "adverb"
      },
      "expansion": "ff",
      "name": "head"
    }
  ],
  "lang": "Dutch",
  "lang_code": "nl",
  "pos": "adv",
  "senses": [
    {
      "alt_of": [
        {
          "extra": "briefly, just",
          "word": "effen"
        }
      ],
      "categories": [],
      "glosses": [
        "Abbreviation of effen; briefly, just."
      ],
      "id": "en-ff-nl-adv-X5Ke4Bzt",
      "links": [
        [
          "effen",
          "effen#Dutch"
        ],
        [
          "briefly",
          "briefly"
        ],
        [
          "just",
          "just"
        ]
      ],
      "raw_glosses": [
        "(informal) Abbreviation of effen; briefly, just."
      ],
      "tags": [
        "abbreviation",
        "alt-of",
        "informal"
      ]
    }
  ],
  "word": "ff"
}

{
  "categories": [
    "Dutch adverbs",
    "Dutch entries with incorrect language header",
    "Dutch lemmas",
    "Dutch phrases",
    "Dutch terms derived from Latin",
    "Pages with 4 entries"
  ],
  "etymology_number": 1,
  "etymology_templates": [
    {
      "args": {
        "1": "nl",
        "2": "la",
        "3": "folio",
        "4": "",
        "5": "on the (next) page"
      },
      "expansion": "Latin folio (“on the (next) page”)",
      "name": "der"
    }
  ],
  "etymology_text": "Abbreviation of Latin folio (“on the (next) page”), ablative of folium (“leaf, page”).",
  "head_templates": [
    {
      "args": {
        "1": "nl",
        "2": "phrase"
      },
      "expansion": "ff",
      "name": "head"
    }
  ],
  "lang": "Dutch",
  "lang_code": "nl",
  "pos": "phrase",
  "senses": [
    {
      "glosses": [
        "ff."
      ],
      "links": [
        [
          "ff.",
          "ff.#English"
        ]
      ]
    }
  ],
  "word": "ff"
}

{
  "categories": [
    "Dutch adverbs",
    "Dutch entries with incorrect language header",
    "Dutch lemmas",
    "Pages with 4 entries"
  ],
  "etymology_number": 2,
  "etymology_text": "When pronounced as the plural of 'f', it sounds like the Dutch word effen.",
  "head_templates": [
    {
      "args": {
        "1": "nl",
        "2": "adverb"
      },
      "expansion": "ff",
      "name": "head"
    }
  ],
  "lang": "Dutch",
  "lang_code": "nl",
  "pos": "adv",
  "senses": [
    {
      "alt_of": [
        {
          "extra": "briefly, just",
          "word": "effen"
        }
      ],
      "categories": [
        "Dutch abbreviations",
        "Dutch informal terms"
      ],
      "glosses": [
        "Abbreviation of effen; briefly, just."
      ],
      "links": [
        [
          "effen",
          "effen#Dutch"
        ],
        [
          "briefly",
          "briefly"
        ],
        [
          "just",
          "just"
        ]
      ],
      "raw_glosses": [
        "(informal) Abbreviation of effen; briefly, just."
      ],
      "tags": [
        "abbreviation",
        "alt-of",
        "informal"
      ]
    }
  ],
  "word": "ff"
}