"travelling post office" meaning in English

{
  "forms": [
    {
      "form": "travelling post offices",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "head": "travelling post office"
      },
      "expansion": "travelling post office (plural travelling post offices)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "British English",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
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          "source": "w"
        },
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          "kind": "other",
          "name": "English entries with topic categories using raw markup",
          "parents": [
            "Entries with topic categories using raw markup",
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          "source": "w"
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          "kind": "other",
          "name": "English terms with non-redundant non-automated sortkeys",
          "parents": [
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            "Entry maintenance"
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          "source": "w"
        },
        {
          "kind": "topical",
          "langcode": "en",
          "name": "Post",
          "orig": "en:Post",
          "parents": [
            "Communication",
            "All topics",
            "Fundamental"
          ],
          "source": "w"
        },
        {
          "kind": "topical",
          "langcode": "en",
          "name": "Rail transportation",
          "orig": "en:Rail transportation",
          "parents": [
            "Transport",
            "All topics",
            "Fundamental"
          ],
          "source": "w"
        }
      ],
      "examples": [
        {
          "ref": "1945 November and December, “Return of the T.P.O.”, in Railway Magazine, pages 311–312",
          "text": "One of the important railway facilities which disappeared on the outbreak of war was the travelling post office. […] T.P.Os. have now been resumed, with the reinstatement on October 1 of those between Euston and Aberdeen, and between Paddington and Penzanze.",
          "type": "quotation"
        }
      ],
      "glosses": [
        "A type of railway coach designed for the carriage and sorting of mail en route."
      ],
      "id": "en-travelling_post_office-en-noun-hIgqLqXF",
      "links": [
        [
          "rail transport",
          "rail transport"
        ],
        [
          "railway",
          "railway"
        ],
        [
          "coach",
          "coach"
        ],
        [
          "mail",
          "mail"
        ],
        [
          "en route",
          "en route"
        ]
      ],
      "raw_glosses": [
        "(rail transport, UK) A type of railway coach designed for the carriage and sorting of mail en route."
      ],
      "synonyms": [
        {
          "tags": [
            "abbreviation"
          ],
          "word": "TPO"
        },
        {
          "tags": [
            "US"
          ],
          "word": "mail car"
        }
      ],
      "tags": [
        "UK"
      ],
      "topics": [
        "rail-transport",
        "railways",
        "transport"
      ]
    }
  ],
  "word": "travelling post office"
}

{
  "forms": [
    {
      "form": "travelling post offices",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "head": "travelling post office"
      },
      "expansion": "travelling post office (plural travelling post offices)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        "British English",
        "English countable nouns",
        "English entries with incorrect language header",
        "English entries with topic categories using raw markup",
        "English lemmas",
        "English multiword terms",
        "English nouns",
        "English terms with non-redundant non-automated sortkeys",
        "English terms with quotations",
        "en:Post",
        "en:Rail transportation"
      ],
      "examples": [
        {
          "ref": "1945 November and December, “Return of the T.P.O.”, in Railway Magazine, pages 311–312",
          "text": "One of the important railway facilities which disappeared on the outbreak of war was the travelling post office. […] T.P.Os. have now been resumed, with the reinstatement on October 1 of those between Euston and Aberdeen, and between Paddington and Penzanze.",
          "type": "quotation"
        }
      ],
      "glosses": [
        "A type of railway coach designed for the carriage and sorting of mail en route."
      ],
      "links": [
        [
          "rail transport",
          "rail transport"
        ],
        [
          "railway",
          "railway"
        ],
        [
          "coach",
          "coach"
        ],
        [
          "mail",
          "mail"
        ],
        [
          "en route",
          "en route"
        ]
      ],
      "raw_glosses": [
        "(rail transport, UK) A type of railway coach designed for the carriage and sorting of mail en route."
      ],
      "tags": [
        "UK"
      ],
      "topics": [
        "rail-transport",
        "railways",
        "transport"
      ]
    }
  ],
  "synonyms": [
    {
      "tags": [
        "abbreviation"
      ],
      "word": "TPO"
    },
    {
      "tags": [
        "US"
      ],
      "word": "mail car"
    }
  ],
  "word": "travelling post office"
}