"psi" meaning in Italian

{
  "head_templates": [
    {
      "args": {
        "1": "mf",
        "2": "#"
      },
      "expansion": "psi m or f (invariable)",
      "name": "it-noun"
    }
  ],
  "hyphenation": [
    "psì"
  ],
  "hyphenations": [
    {
      "parts": [
        "psì"
      ]
    }
  ],
  "lang": "Italian",
  "lang_code": "it",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "Italian entries with incorrect language header",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with 12 entries",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "langcode": "it",
          "name": "Greek letter names",
          "orig": "it:Greek letter names",
          "parents": [],
          "source": "w"
        }
      ],
      "glosses": [
        "psi (Greek letter)"
      ],
      "id": "en-psi-it-noun-zhAvR1tg",
      "links": [
        [
          "psi",
          "psi#English"
        ]
      ],
      "tags": [
        "feminine",
        "invariable",
        "masculine"
      ]
    }
  ],
  "sounds": [
    {
      "ipa": "/ˈpsi/"
    },
    {
      "rhymes": "-i"
    }
  ],
  "word": "psi"
}

{
  "head_templates": [
    {
      "args": {
        "1": "mf",
        "2": "#"
      },
      "expansion": "psi m or f (invariable)",
      "name": "it-noun"
    }
  ],
  "hyphenation": [
    "psì"
  ],
  "hyphenations": [
    {
      "parts": [
        "psì"
      ]
    }
  ],
  "lang": "Italian",
  "lang_code": "it",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        "Italian 1-syllable words",
        "Italian countable nouns",
        "Italian entries with incorrect language header",
        "Italian feminine nouns",
        "Italian indeclinable nouns",
        "Italian lemmas",
        "Italian masculine nouns",
        "Italian nouns",
        "Italian nouns with multiple genders",
        "Italian terms with IPA pronunciation",
        "Pages with 12 entries",
        "Pages with entries",
        "Rhymes:Italian/i",
        "Rhymes:Italian/i/1 syllable",
        "it:Greek letter names"
      ],
      "glosses": [
        "psi (Greek letter)"
      ],
      "links": [
        [
          "psi",
          "psi#English"
        ]
      ],
      "tags": [
        "feminine",
        "invariable",
        "masculine"
      ]
    }
  ],
  "sounds": [
    {
      "ipa": "/ˈpsi/"
    },
    {
      "rhymes": "-i"
    }
  ],
  "word": "psi"
}