"final sigma" meaning in English

{
  "forms": [
    {
      "form": "final sigmas",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "final sigma (plural final sigmas)",
      "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": "English entries with topic categories using raw markup",
          "parents": [
            "Entries with topic categories using raw markup",
            "Entry maintenance"
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          "source": "w"
        },
        {
          "kind": "other",
          "name": "English terms with non-redundant non-automated sortkeys",
          "parents": [
            "Terms with non-redundant non-automated sortkeys",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "topical",
          "langcode": "en",
          "name": "Greek letter names",
          "orig": "en:Greek letter names",
          "parents": [
            "Letter names",
            "Letters, symbols, and punctuation",
            "Names",
            "Orthography",
            "All topics",
            "Proper nouns",
            "Terms by semantic function",
            "Writing",
            "Fundamental",
            "Nouns",
            "Human behaviour",
            "Language",
            "Lemmas",
            "Human",
            "Communication"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "The form of the Greek letter sigma only ever used as the last letter of a word: ς."
      ],
      "id": "en-final_sigma-en-noun-pK9ZofUg",
      "links": [
        [
          "Greek",
          "Greek"
        ],
        [
          "ς",
          "ς"
        ]
      ],
      "related": [
        {
          "word": "lunate sigma"
        }
      ],
      "translations": [
        {
          "code": "el",
          "lang": "Greek",
          "roman": "sígma telikó",
          "sense": "form of the Greek letter sigma",
          "word": "σίγμα τελικό"
        }
      ]
    }
  ],
  "word": "final sigma"
}

{
  "forms": [
    {
      "form": "final sigmas",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "final sigma (plural final sigmas)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "related": [
    {
      "word": "lunate sigma"
    }
  ],
  "senses": [
    {
      "categories": [
        "English countable nouns",
        "English entries with incorrect language header",
        "English entries with topic categories using raw markup",
        "English lemmas",
        "English multiword terms",
        "English nouns",
        "English terms with non-redundant non-automated sortkeys",
        "en:Greek letter names"
      ],
      "glosses": [
        "The form of the Greek letter sigma only ever used as the last letter of a word: ς."
      ],
      "links": [
        [
          "Greek",
          "Greek"
        ],
        [
          "ς",
          "ς"
        ]
      ]
    }
  ],
  "translations": [
    {
      "code": "el",
      "lang": "Greek",
      "roman": "sígma telikó",
      "sense": "form of the Greek letter sigma",
      "word": "σίγμα τελικό"
    }
  ],
  "word": "final sigma"
}