"relief tube" meaning in English

{
  "forms": [
    {
      "form": "relief tubes",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "relief tube (plural relief tubes)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with 1 entry",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "topical",
          "langcode": "en",
          "name": "Aviation",
          "orig": "en:Aviation",
          "parents": [
            "Aeronautics",
            "Transport",
            "Sciences",
            "All topics",
            "Fundamental"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "A tube built into an aircraft allowing the crew to urinate while in flight."
      ],
      "id": "en-relief_tube-en-noun-LIyu-krk",
      "links": [
        [
          "aviation",
          "aviation"
        ],
        [
          "aircraft",
          "aircraft"
        ],
        [
          "crew",
          "crew"
        ],
        [
          "urinate",
          "urinate"
        ],
        [
          "flight",
          "flight"
        ]
      ],
      "raw_glosses": [
        "(aviation, historical) A tube built into an aircraft allowing the crew to urinate while in flight."
      ],
      "related": [
        {
          "word": "piddle pack"
        }
      ],
      "tags": [
        "historical"
      ],
      "topics": [
        "aeronautics",
        "aerospace",
        "aviation",
        "business",
        "engineering",
        "natural-sciences",
        "physical-sciences"
      ]
    }
  ],
  "word": "relief tube"
}

{
  "forms": [
    {
      "form": "relief tubes",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "relief tube (plural relief tubes)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "related": [
    {
      "word": "piddle pack"
    }
  ],
  "senses": [
    {
      "categories": [
        "English countable nouns",
        "English entries with incorrect language header",
        "English lemmas",
        "English multiword terms",
        "English nouns",
        "English terms with historical senses",
        "Pages with 1 entry",
        "Pages with entries",
        "en:Aviation"
      ],
      "glosses": [
        "A tube built into an aircraft allowing the crew to urinate while in flight."
      ],
      "links": [
        [
          "aviation",
          "aviation"
        ],
        [
          "aircraft",
          "aircraft"
        ],
        [
          "crew",
          "crew"
        ],
        [
          "urinate",
          "urinate"
        ],
        [
          "flight",
          "flight"
        ]
      ],
      "raw_glosses": [
        "(aviation, historical) A tube built into an aircraft allowing the crew to urinate while in flight."
      ],
      "tags": [
        "historical"
      ],
      "topics": [
        "aeronautics",
        "aerospace",
        "aviation",
        "business",
        "engineering",
        "natural-sciences",
        "physical-sciences"
      ]
    }
  ],
  "word": "relief tube"
}