"real jam" meaning in English

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      "expansion": "real jam (uncountable)",
      "name": "en-noun"
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  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
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          "kind": "other",
          "name": "British English",
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      "examples": [
        {
          "text": "That's the real jam!",
          "type": "example"
        },
        {
          "ref": "George Augustus Sala, The Story of Jack the Painter, in 1863, Tales and Essays (volume 3, page 10)",
          "text": "It's real jam, that little pictur his . I wouldn't mind springin' the price to a century. There! Shall I send my boy round to tell him so?"
        },
        {
          "ref": "1877, Punch, page 134:",
          "text": "It was real jam to see little NORRIS, who was out for the first time, in a horrid state about his four greys.",
          "type": "quote"
        }
      ],
      "glosses": [
        "Anything exceptionally good."
      ],
      "id": "en-real_jam-en-noun-EvLuufJ2",
      "raw_glosses": [
        "(UK, slang) Anything exceptionally good."
      ],
      "tags": [
        "UK",
        "slang",
        "uncountable"
      ]
    }
  ],
  "word": "real jam"
}

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      "expansion": "real jam (uncountable)",
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  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
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        "British English",
        "English entries with incorrect language header",
        "English lemmas",
        "English multiword terms",
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      "examples": [
        {
          "text": "That's the real jam!",
          "type": "example"
        },
        {
          "ref": "George Augustus Sala, The Story of Jack the Painter, in 1863, Tales and Essays (volume 3, page 10)",
          "text": "It's real jam, that little pictur his . I wouldn't mind springin' the price to a century. There! Shall I send my boy round to tell him so?"
        },
        {
          "ref": "1877, Punch, page 134:",
          "text": "It was real jam to see little NORRIS, who was out for the first time, in a horrid state about his four greys.",
          "type": "quote"
        }
      ],
      "glosses": [
        "Anything exceptionally good."
      ],
      "raw_glosses": [
        "(UK, slang) Anything exceptionally good."
      ],
      "tags": [
        "UK",
        "slang",
        "uncountable"
      ]
    }
  ],
  "word": "real jam"
}