"-о-" meaning in Bulgarian

{
  "etymology_templates": [
    {
      "args": {
        "1": "inherited"
      },
      "expansion": "inherited",
      "name": "glossary"
    },
    {
      "args": {
        "1": "bg",
        "2": "cu",
        "3": "-о-",
        "4": "",
        "5": "",
        "g": "",
        "g2": "",
        "g3": "",
        "id": "",
        "lit": "",
        "nocat": "",
        "pos": "",
        "sc": "",
        "sort": "",
        "tr": "",
        "ts": ""
      },
      "expansion": "Old Church Slavonic -о- (-o-)",
      "name": "inh"
    },
    {
      "args": {
        "1": "bg",
        "2": "cu",
        "3": "-о-",
        "nocap": "1"
      },
      "expansion": "inherited from Old Church Slavonic -о- (-o-)",
      "name": "inh+"
    },
    {
      "args": {
        "1": "bg",
        "2": "sla-pro",
        "3": "*-o-"
      },
      "expansion": "Proto-Slavic *-o-",
      "name": "inh"
    },
    {
      "args": {
        "1": "bg",
        "2": "la",
        "3": "-o-"
      },
      "expansion": "Latin -o-",
      "name": "bor"
    },
    {
      "args": {
        "1": "bg",
        "2": "grc",
        "3": "-ό-"
      },
      "expansion": "Ancient Greek -ό- (-ó-)",
      "name": "bor"
    },
    {
      "args": {
        "1": "grc",
        "2": "-ο-"
      },
      "expansion": "-ο- (-o-)",
      "name": "m"
    }
  ],
  "etymology_text": "For native terms, inherited from Old Church Slavonic -о- (-o-), from Proto-Slavic *-o-.\nFor borrowings, from Latin -o- or Ancient Greek -ό- (-ó-)/-ο- (-o-).",
  "forms": [
    {
      "form": "-o-",
      "tags": [
        "alternative"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "bg",
        "2": "interfix"
      },
      "expansion": "-о- • (-o-)",
      "name": "head"
    }
  ],
  "lang": "Bulgarian",
  "lang_code": "bg",
  "pos": "interfix",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "Bulgarian entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Bulgarian interfixes",
          "parents": [],
          "source": "w"
        }
      ],
      "glosses": [
        "Used to form compound words. Usually excrescent."
      ],
      "id": "en--о--bg-interfix-jHT1lGff",
      "synonyms": [
        {
          "roman": "-e-",
          "word": "-е-"
        }
      ],
      "tags": [
        "morpheme"
      ]
    }
  ],
  "word": "-о-"
}

{
  "etymology_templates": [
    {
      "args": {
        "1": "inherited"
      },
      "expansion": "inherited",
      "name": "glossary"
    },
    {
      "args": {
        "1": "bg",
        "2": "cu",
        "3": "-о-",
        "4": "",
        "5": "",
        "g": "",
        "g2": "",
        "g3": "",
        "id": "",
        "lit": "",
        "nocat": "",
        "pos": "",
        "sc": "",
        "sort": "",
        "tr": "",
        "ts": ""
      },
      "expansion": "Old Church Slavonic -о- (-o-)",
      "name": "inh"
    },
    {
      "args": {
        "1": "bg",
        "2": "cu",
        "3": "-о-",
        "nocap": "1"
      },
      "expansion": "inherited from Old Church Slavonic -о- (-o-)",
      "name": "inh+"
    },
    {
      "args": {
        "1": "bg",
        "2": "sla-pro",
        "3": "*-o-"
      },
      "expansion": "Proto-Slavic *-o-",
      "name": "inh"
    },
    {
      "args": {
        "1": "bg",
        "2": "la",
        "3": "-o-"
      },
      "expansion": "Latin -o-",
      "name": "bor"
    },
    {
      "args": {
        "1": "bg",
        "2": "grc",
        "3": "-ό-"
      },
      "expansion": "Ancient Greek -ό- (-ó-)",
      "name": "bor"
    },
    {
      "args": {
        "1": "grc",
        "2": "-ο-"
      },
      "expansion": "-ο- (-o-)",
      "name": "m"
    }
  ],
  "etymology_text": "For native terms, inherited from Old Church Slavonic -о- (-o-), from Proto-Slavic *-o-.\nFor borrowings, from Latin -o- or Ancient Greek -ό- (-ó-)/-ο- (-o-).",
  "forms": [
    {
      "form": "-o-",
      "tags": [
        "alternative"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "bg",
        "2": "interfix"
      },
      "expansion": "-о- • (-o-)",
      "name": "head"
    }
  ],
  "lang": "Bulgarian",
  "lang_code": "bg",
  "pos": "interfix",
  "senses": [
    {
      "categories": [
        "Bulgarian entries with incorrect language header",
        "Bulgarian interfixes",
        "Bulgarian lemmas",
        "Bulgarian terms borrowed from Ancient Greek",
        "Bulgarian terms borrowed from Latin",
        "Bulgarian terms derived from Ancient Greek",
        "Bulgarian terms derived from Latin",
        "Bulgarian terms derived from Old Church Slavonic",
        "Bulgarian terms derived from Proto-Slavic",
        "Bulgarian terms inherited from Old Church Slavonic",
        "Bulgarian terms inherited from Proto-Slavic"
      ],
      "glosses": [
        "Used to form compound words. Usually excrescent."
      ],
      "tags": [
        "morpheme"
      ]
    }
  ],
  "synonyms": [
    {
      "roman": "-e-",
      "word": "-е-"
    }
  ],
  "word": "-о-"
}