"z-direction" meaning in English

{
  "head_templates": [
    {
      "args": {
        "1": "en",
        "2": "noun",
        "head": "z-direction"
      },
      "expansion": "z-direction",
      "name": "head"
    }
  ],
  "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": "English terms containing italics",
          "parents": [
            "Terms containing italics",
            "Terms by orthographic property",
            "Terms by lexical property"
          ],
          "source": "w"
        },
        {
          "kind": "topical",
          "langcode": "en",
          "name": "Algebraic geometry",
          "orig": "en:Algebraic geometry",
          "parents": [
            "Algebra",
            "Geometry",
            "Mathematics",
            "Formal sciences",
            "Sciences",
            "All topics",
            "Fundamental"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "The direction aligned with the z-axis of a coordinate system."
      ],
      "id": "en-z-direction-en-noun-KtcvZzv-",
      "links": [
        [
          "algebraic geometry",
          "algebraic geometry"
        ],
        [
          "z-axis",
          "z-axis"
        ],
        [
          "coordinate system",
          "coordinate system"
        ]
      ],
      "raw_glosses": [
        "(algebraic geometry) The direction aligned with the z-axis of a coordinate system."
      ],
      "related": [
        {
          "word": "x-direction"
        },
        {
          "word": "y-direction"
        }
      ],
      "topics": [
        "algebraic-geometry",
        "geometry",
        "mathematics",
        "sciences"
      ]
    }
  ],
  "word": "z-direction"
}

{
  "head_templates": [
    {
      "args": {
        "1": "en",
        "2": "noun",
        "head": "z-direction"
      },
      "expansion": "z-direction",
      "name": "head"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "related": [
    {
      "word": "x-direction"
    },
    {
      "word": "y-direction"
    }
  ],
  "senses": [
    {
      "categories": [
        "English entries with incorrect language header",
        "English lemmas",
        "English multiword terms",
        "English nouns",
        "English terms containing italics",
        "en:Algebraic geometry"
      ],
      "glosses": [
        "The direction aligned with the z-axis of a coordinate system."
      ],
      "links": [
        [
          "algebraic geometry",
          "algebraic geometry"
        ],
        [
          "z-axis",
          "z-axis"
        ],
        [
          "coordinate system",
          "coordinate system"
        ]
      ],
      "raw_glosses": [
        "(algebraic geometry) The direction aligned with the z-axis of a coordinate system."
      ],
      "topics": [
        "algebraic-geometry",
        "geometry",
        "mathematics",
        "sciences"
      ]
    }
  ],
  "word": "z-direction"
}