"sub-aqueous" meaning in English

{
  "etymology_templates": [
    {
      "args": {
        "1": "en",
        "2": "sub-",
        "3": "aqueous"
      },
      "expansion": "sub- + aqueous",
      "name": "af"
    }
  ],
  "etymology_text": "From sub- + aqueous.",
  "head_templates": [
    {
      "args": {
        "1": "-"
      },
      "expansion": "sub-aqueous (not comparable)",
      "name": "en-adj"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "adj",
  "senses": [
    {
      "alt_of": [
        {
          "word": "subaqueous"
        }
      ],
      "categories": [
        {
          "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 terms prefixed with sub-",
          "parents": [],
          "source": "w"
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          "kind": "other",
          "name": "Pages with 1 entry",
          "parents": [],
          "source": "w"
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          "kind": "other",
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          "parents": [],
          "source": "w"
        }
      ],
      "examples": [
        {
          "ref": "1948 September and October, “Weekend Works in the Severn Tunnel”, in Railway Magazine, page 298:",
          "text": "The tunnel is 4 miles 628 yd. long, and is the longest tunnel on a British main-line railway, and the longest sub-aqueous tunnel in the world.",
          "type": "quote"
        },
        {
          "ref": "2012, Andrew Martin, Underground Overground: A passenger's history of the Tube, Profile Books, →ISBN, page 87:",
          "text": "[...] he'd been hoping to build a bridge over the River Nova in St Petersburg. The Russians would eventually decide to go under the river, but not before Brunel had shown the way, by building the first sub-aqueous tunnel in the world.",
          "type": "quote"
        }
      ],
      "glosses": [
        "Alternative form of subaqueous."
      ],
      "id": "en-sub-aqueous-en-adj-A7IVdH0x",
      "links": [
        [
          "subaqueous",
          "subaqueous#English"
        ]
      ],
      "tags": [
        "alt-of",
        "alternative",
        "not-comparable"
      ]
    }
  ],
  "word": "sub-aqueous"
}

{
  "etymology_templates": [
    {
      "args": {
        "1": "en",
        "2": "sub-",
        "3": "aqueous"
      },
      "expansion": "sub- + aqueous",
      "name": "af"
    }
  ],
  "etymology_text": "From sub- + aqueous.",
  "head_templates": [
    {
      "args": {
        "1": "-"
      },
      "expansion": "sub-aqueous (not comparable)",
      "name": "en-adj"
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  "lang": "English",
  "lang_code": "en",
  "pos": "adj",
  "senses": [
    {
      "alt_of": [
        {
          "word": "subaqueous"
        }
      ],
      "categories": [
        "English adjectives",
        "English entries with incorrect language header",
        "English lemmas",
        "English multiword terms",
        "English terms prefixed with sub-",
        "English terms with quotations",
        "English uncomparable adjectives",
        "Pages with 1 entry",
        "Pages with entries"
      ],
      "examples": [
        {
          "ref": "1948 September and October, “Weekend Works in the Severn Tunnel”, in Railway Magazine, page 298:",
          "text": "The tunnel is 4 miles 628 yd. long, and is the longest tunnel on a British main-line railway, and the longest sub-aqueous tunnel in the world.",
          "type": "quote"
        },
        {
          "ref": "2012, Andrew Martin, Underground Overground: A passenger's history of the Tube, Profile Books, →ISBN, page 87:",
          "text": "[...] he'd been hoping to build a bridge over the River Nova in St Petersburg. The Russians would eventually decide to go under the river, but not before Brunel had shown the way, by building the first sub-aqueous tunnel in the world.",
          "type": "quote"
        }
      ],
      "glosses": [
        "Alternative form of subaqueous."
      ],
      "links": [
        [
          "subaqueous",
          "subaqueous#English"
        ]
      ],
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    }
  ],
  "word": "sub-aqueous"
}