"быти" meaning in Vieux slave

{
  "categories": [
    {
      "kind": "other",
      "name": "Mots en vieux slave issus d’un mot en proto-slave",
      "parents": [],
      "source": "w"
    },
    {
      "kind": "other",
      "name": "Verbes en vieux slave",
      "parents": [],
      "source": "w"
    },
    {
      "kind": "other",
      "name": "Verbes imperfectifs en vieux slave",
      "parents": [],
      "source": "w"
    },
    {
      "kind": "other",
      "name": "Vieux slave",
      "orig": "vieux slave",
      "parents": [],
      "source": "w"
    },
    {
      "kind": "other",
      "name": "Étymologies en vieux slave incluant une reconstruction",
      "parents": [],
      "source": "w"
    }
  ],
  "derived": [
    {
      "lang": "Bas-sorabe",
      "lang_code": "dsb",
      "word": "byś"
    },
    {
      "lang": "Bulgare",
      "lang_code": "bg",
      "word": "съм"
    },
    {
      "lang": "Bulgare",
      "lang_code": "bg",
      "word": "бъда"
    },
    {
      "lang": "Kachoube",
      "lang_code": "csb",
      "word": "bëc"
    },
    {
      "lang": "Russe",
      "lang_code": "ru",
      "word": "быть"
    },
    {
      "lang": "Ukrainien",
      "lang_code": "uk",
      "word": "бути"
    }
  ],
  "etymology_texts": [
    "Du proto-slave *byti, issu de l’indo-européen commun *bʰuH- qui donne l’anglais to be, le latin fio, etc.",
    "Comme le latin sum, esse, futurus, le verbe быти est hétéroclite ; au latin sum correspond ѥсмь."
  ],
  "lang": "Vieux slave",
  "lang_code": "cu",
  "pos": "verb",
  "pos_title": "Verbe",
  "senses": [
    {
      "glosses": [
        "Être."
      ],
      "id": "fr-быти-cu-verb-XMdFa46n"
    }
  ],
  "tags": [
    "imperfective"
  ],
  "word": "быти"
}

{
  "categories": [
    "Mots en vieux slave issus d’un mot en proto-slave",
    "Verbes en vieux slave",
    "Verbes imperfectifs en vieux slave",
    "vieux slave",
    "Étymologies en vieux slave incluant une reconstruction"
  ],
  "derived": [
    {
      "lang": "Bas-sorabe",
      "lang_code": "dsb",
      "word": "byś"
    },
    {
      "lang": "Bulgare",
      "lang_code": "bg",
      "word": "съм"
    },
    {
      "lang": "Bulgare",
      "lang_code": "bg",
      "word": "бъда"
    },
    {
      "lang": "Kachoube",
      "lang_code": "csb",
      "word": "bëc"
    },
    {
      "lang": "Russe",
      "lang_code": "ru",
      "word": "быть"
    },
    {
      "lang": "Ukrainien",
      "lang_code": "uk",
      "word": "бути"
    }
  ],
  "etymology_texts": [
    "Du proto-slave *byti, issu de l’indo-européen commun *bʰuH- qui donne l’anglais to be, le latin fio, etc.",
    "Comme le latin sum, esse, futurus, le verbe быти est hétéroclite ; au latin sum correspond ѥсмь."
  ],
  "lang": "Vieux slave",
  "lang_code": "cu",
  "pos": "verb",
  "pos_title": "Verbe",
  "senses": [
    {
      "glosses": [
        "Être."
      ]
    }
  ],
  "tags": [
    "imperfective"
  ],
  "word": "быти"
}