"retention line" meaning in All languages combined

{
  "forms": [
    {
      "form": "retention lines",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "retention line (plural retention lines)",
      "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": "Travel",
          "orig": "en:Travel",
          "parents": [
            "Human activity",
            "Transport",
            "Human behaviour",
            "All topics",
            "Human",
            "Fundamental"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "A future-dated line of text put in to an airline reservation system or GDS to delay the booking being moved to archives."
      ],
      "id": "en-retention_line-en-noun-TpvgjYh0",
      "links": [
        [
          "travel",
          "travel"
        ]
      ],
      "raw_glosses": [
        "(travel) A future-dated line of text put in to an airline reservation system or GDS to delay the booking being moved to archives."
      ],
      "topics": [
        "lifestyle",
        "tourism",
        "transport",
        "travel"
      ]
    }
  ],
  "word": "retention line"
}

{
  "forms": [
    {
      "form": "retention lines",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "retention line (plural retention lines)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        "English countable nouns",
        "English entries with incorrect language header",
        "English lemmas",
        "English multiword terms",
        "English nouns",
        "Pages with 1 entry",
        "Pages with entries",
        "en:Travel"
      ],
      "glosses": [
        "A future-dated line of text put in to an airline reservation system or GDS to delay the booking being moved to archives."
      ],
      "links": [
        [
          "travel",
          "travel"
        ]
      ],
      "raw_glosses": [
        "(travel) A future-dated line of text put in to an airline reservation system or GDS to delay the booking being moved to archives."
      ],
      "topics": [
        "lifestyle",
        "tourism",
        "transport",
        "travel"
      ]
    }
  ],
  "word": "retention line"
}