"ψῖ" meaning in Grec ancien

{
  "categories": [
    {
      "kind": "other",
      "name": "Noms communs en grec ancien",
      "parents": [],
      "source": "w"
    },
    {
      "kind": "other",
      "name": "Noms des lettres grecques en grec ancien",
      "parents": [],
      "source": "w"
    },
    {
      "kind": "other",
      "name": "Grec ancien",
      "orig": "grec ancien",
      "parents": [],
      "source": "w"
    }
  ],
  "lang": "Grec ancien",
  "lang_code": "grc",
  "pos": "noun",
  "pos_title": "Nom commun",
  "raw_tags": [
    "ψῖ, psî"
  ],
  "senses": [
    {
      "glosses": [
        "Psi, la vingt-troisième lettre de l’alphabet grec. S’écrit « Ψ » en majuscule, et « ψ » en minuscule."
      ],
      "id": "fr-ψῖ-grc-noun-j4x7z~rx"
    }
  ],
  "sounds": [
    {
      "ipa": "*\\ˈpʰsiːˌ\\"
    }
  ],
  "tags": [
    "neuter"
  ],
  "word": "ψῖ"
}

{
  "categories": [
    "Noms communs en grec ancien",
    "Noms des lettres grecques en grec ancien",
    "grec ancien"
  ],
  "lang": "Grec ancien",
  "lang_code": "grc",
  "pos": "noun",
  "pos_title": "Nom commun",
  "raw_tags": [
    "ψῖ, psî"
  ],
  "senses": [
    {
      "glosses": [
        "Psi, la vingt-troisième lettre de l’alphabet grec. S’écrit « Ψ » en majuscule, et « ψ » en minuscule."
      ]
    }
  ],
  "sounds": [
    {
      "ipa": "*\\ˈpʰsiːˌ\\"
    }
  ],
  "tags": [
    "neuter"
  ],
  "word": "ψῖ"
}