"F/X" meaning in English

{
  "etymology_text": "From the pronunciation of the word \"effects\" being similar to the pronunciation of the letters \"F\" and \"X\".",
  "forms": [
    {
      "form": "X",
      "tags": [
        "canonical",
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "p"
      },
      "expansion": "X pl (plural only)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "alt_of": [
        {
          "word": "special effects"
        }
      ],
      "categories": [
        {
          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "English pluralia tantum",
          "parents": [
            "Pluralia tantum",
            "Nouns",
            "Lemmas"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "Initialism of special effects."
      ],
      "hyponyms": [
        {
          "english": "sound effects",
          "word": "SFX"
        },
        {
          "english": "visual effects",
          "word": "VFX"
        }
      ],
      "id": "en-F/X-en-noun-0hwm0Amv",
      "links": [
        [
          "special effects",
          "special effects#English"
        ]
      ],
      "synonyms": [
        {
          "word": "SFX"
        },
        {
          "word": "S.F.X."
        },
        {
          "word": "FX"
        }
      ],
      "tags": [
        "abbreviation",
        "alt-of",
        "initialism",
        "plural",
        "plural-only"
      ]
    }
  ],
  "word": "F/X"
}

{
  "etymology_text": "From the pronunciation of the word \"effects\" being similar to the pronunciation of the letters \"F\" and \"X\".",
  "forms": [
    {
      "form": "X",
      "tags": [
        "canonical",
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "p"
      },
      "expansion": "X pl (plural only)",
      "name": "en-noun"
    }
  ],
  "hyponyms": [
    {
      "english": "sound effects",
      "word": "SFX"
    },
    {
      "english": "visual effects",
      "word": "VFX"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "alt_of": [
        {
          "word": "special effects"
        }
      ],
      "categories": [
        "English entries with incorrect language header",
        "English initialisms",
        "English lemmas",
        "English nouns",
        "English pluralia tantum",
        "English words without vowels"
      ],
      "glosses": [
        "Initialism of special effects."
      ],
      "links": [
        [
          "special effects",
          "special effects#English"
        ]
      ],
      "tags": [
        "abbreviation",
        "alt-of",
        "initialism",
        "plural",
        "plural-only"
      ]
    }
  ],
  "synonyms": [
    {
      "word": "SFX"
    },
    {
      "word": "S.F.X."
    },
    {
      "word": "FX"
    }
  ],
  "word": "F/X"
}