"царевичу" meaning in Ukrainien

{
  "categories": [
    {
      "kind": "other",
      "name": "Formes de noms communs en ukrainien",
      "parents": [],
      "source": "w"
    },
    {
      "kind": "other",
      "name": "Ukrainien",
      "orig": "ukrainien",
      "parents": [],
      "source": "w"
    }
  ],
  "lang": "Ukrainien",
  "lang_code": "uk",
  "pos": "noun",
  "pos_title": "Forme de nom commun",
  "raw_tags": [
    "masculin animé"
  ],
  "senses": [
    {
      "form_of": [
        {
          "word": "царе́вич"
        }
      ],
      "glosses": [
        "Datif singulier de царе́вич."
      ],
      "id": "fr-царевичу-uk-noun-b9ec8uVb"
    },
    {
      "form_of": [
        {
          "word": "царе́вич"
        }
      ],
      "glosses": [
        "Locatif singulier de царе́вич."
      ],
      "id": "fr-царевичу-uk-noun-b7MHmKTL"
    },
    {
      "form_of": [
        {
          "word": "царе́вич"
        }
      ],
      "glosses": [
        "Vocatif singulier de царе́вич."
      ],
      "id": "fr-царевичу-uk-noun-J6J7HZXv"
    }
  ],
  "tags": [
    "form-of"
  ],
  "word": "царевичу"
}

{
  "categories": [
    "Formes de noms communs en ukrainien",
    "ukrainien"
  ],
  "lang": "Ukrainien",
  "lang_code": "uk",
  "pos": "noun",
  "pos_title": "Forme de nom commun",
  "raw_tags": [
    "masculin animé"
  ],
  "senses": [
    {
      "form_of": [
        {
          "word": "царе́вич"
        }
      ],
      "glosses": [
        "Datif singulier de царе́вич."
      ]
    },
    {
      "form_of": [
        {
          "word": "царе́вич"
        }
      ],
      "glosses": [
        "Locatif singulier de царе́вич."
      ]
    },
    {
      "form_of": [
        {
          "word": "царе́вич"
        }
      ],
      "glosses": [
        "Vocatif singulier de царе́вич."
      ]
    }
  ],
  "tags": [
    "form-of"
  ],
  "word": "царевичу"
}