"tis" meaning in Tok Pisin

{
  "etymology_templates": [
    {
      "args": {
        "1": "tpi",
        "2": "en",
        "3": "teeth"
      },
      "expansion": "English teeth",
      "name": "inh"
    }
  ],
  "etymology_text": "From English teeth.",
  "head_templates": [
    {
      "args": {
        "1": "tpi",
        "2": "noun"
      },
      "expansion": "tis",
      "name": "head"
    }
  ],
  "lang": "Tok Pisin",
  "lang_code": "tpi",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "Tok Pisin entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "topical",
          "langcode": "tpi",
          "name": "Anatomy",
          "orig": "tpi:Anatomy",
          "parents": [
            "Biology",
            "Medicine",
            "Sciences",
            "All topics",
            "Fundamental"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "tooth"
      ],
      "id": "en-tis-tpi-noun-lyLUpLWc",
      "links": [
        [
          "anatomy",
          "anatomy"
        ],
        [
          "tooth",
          "tooth"
        ]
      ],
      "raw_glosses": [
        "(anatomy) tooth"
      ],
      "topics": [
        "anatomy",
        "medicine",
        "sciences"
      ]
    }
  ],
  "word": "tis"
}

{
  "etymology_templates": [
    {
      "args": {
        "1": "tpi",
        "2": "en",
        "3": "teeth"
      },
      "expansion": "English teeth",
      "name": "inh"
    }
  ],
  "etymology_text": "From English teeth.",
  "head_templates": [
    {
      "args": {
        "1": "tpi",
        "2": "noun"
      },
      "expansion": "tis",
      "name": "head"
    }
  ],
  "lang": "Tok Pisin",
  "lang_code": "tpi",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        "Tok Pisin entries with incorrect language header",
        "Tok Pisin lemmas",
        "Tok Pisin nouns",
        "Tok Pisin terms derived from English",
        "Tok Pisin terms inherited from English",
        "tpi:Anatomy"
      ],
      "glosses": [
        "tooth"
      ],
      "links": [
        [
          "anatomy",
          "anatomy"
        ],
        [
          "tooth",
          "tooth"
        ]
      ],
      "raw_glosses": [
        "(anatomy) tooth"
      ],
      "topics": [
        "anatomy",
        "medicine",
        "sciences"
      ]
    }
  ],
  "word": "tis"
}