"-o-" meaning in Latin

{
  "etymology_templates": [
    {
      "args": {
        "1": "la",
        "2": "grc",
        "3": "-ο-"
      },
      "expansion": "Ancient Greek -ο- (-o-)",
      "name": "der"
    },
    {
      "args": {
        "1": "grc",
        "2": "-ό-"
      },
      "expansion": "-ό- (-ó-)",
      "name": "m"
    },
    {
      "args": {
        "1": "grc",
        "2": "δημοκρατία"
      },
      "expansion": "δημοκρατία (dēmokratía)",
      "name": "m"
    },
    {
      "args": {
        "1": "grc",
        "2": "μητρόπολις"
      },
      "expansion": "μητρόπολις (mētrópolis)",
      "name": "m"
    }
  ],
  "etymology_text": "Adopted from the thematic vowel in Ancient Greek -ο- (-o-) and -ό- (-ó-), often used to form nominal compounds. In Ancient Greek, the connective suffix originates in compounds where the first member is thematic, such as δημοκρατία (dēmokratía), but was extended by analogy to other stems, such as μητρόπολις (mētrópolis). The suffix was borrowed as a connective into Latin, mainly in compounds of Greek origin.\nThe suffix becomes productive and forms new compounds in learned humanist Latin, from the Renaissance. The connective is especially productive in connecting ethnonyms or geographical terms; genuine Greek stems include Gallo-, and Syro-, but most are of medieval or modern origin, productive from the 15th century, such as Anglo-, Graeco- or Latino-.",
  "head_templates": [
    {
      "args": {
        "1": "la",
        "2": "interfix"
      },
      "expansion": "-o-",
      "name": "head"
    }
  ],
  "lang": "Latin",
  "lang_code": "la",
  "pos": "interfix",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "Latin entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Latin interfixes",
          "parents": [],
          "source": "w"
        }
      ],
      "glosses": [
        "Suffix forming nominal compounds (such as anglosaxonicus (“Anglo-Saxon”), from Anglus (“Angle, English”) and saxonicus (“Saxon”))."
      ],
      "id": "en--o--la-interfix-4eG6z-Xh",
      "links": [
        [
          "anglosaxonicus",
          "anglosaxonicus#Latin"
        ],
        [
          "Anglus",
          "Anglus#Latin"
        ],
        [
          "saxonicus",
          "saxonicus#Latin"
        ]
      ],
      "raw_glosses": [
        "(post-classical Latin) Suffix forming nominal compounds (such as anglosaxonicus (“Anglo-Saxon”), from Anglus (“Angle, English”) and saxonicus (“Saxon”))."
      ],
      "tags": [
        "Latin",
        "morpheme",
        "obsolete"
      ]
    }
  ],
  "word": "-o-"
}

{
  "etymology_templates": [
    {
      "args": {
        "1": "la",
        "2": "grc",
        "3": "-ο-"
      },
      "expansion": "Ancient Greek -ο- (-o-)",
      "name": "der"
    },
    {
      "args": {
        "1": "grc",
        "2": "-ό-"
      },
      "expansion": "-ό- (-ó-)",
      "name": "m"
    },
    {
      "args": {
        "1": "grc",
        "2": "δημοκρατία"
      },
      "expansion": "δημοκρατία (dēmokratía)",
      "name": "m"
    },
    {
      "args": {
        "1": "grc",
        "2": "μητρόπολις"
      },
      "expansion": "μητρόπολις (mētrópolis)",
      "name": "m"
    }
  ],
  "etymology_text": "Adopted from the thematic vowel in Ancient Greek -ο- (-o-) and -ό- (-ó-), often used to form nominal compounds. In Ancient Greek, the connective suffix originates in compounds where the first member is thematic, such as δημοκρατία (dēmokratía), but was extended by analogy to other stems, such as μητρόπολις (mētrópolis). The suffix was borrowed as a connective into Latin, mainly in compounds of Greek origin.\nThe suffix becomes productive and forms new compounds in learned humanist Latin, from the Renaissance. The connective is especially productive in connecting ethnonyms or geographical terms; genuine Greek stems include Gallo-, and Syro-, but most are of medieval or modern origin, productive from the 15th century, such as Anglo-, Graeco- or Latino-.",
  "head_templates": [
    {
      "args": {
        "1": "la",
        "2": "interfix"
      },
      "expansion": "-o-",
      "name": "head"
    }
  ],
  "lang": "Latin",
  "lang_code": "la",
  "pos": "interfix",
  "senses": [
    {
      "categories": [
        "Latin entries with incorrect language header",
        "Latin interfixes",
        "Latin lemmas",
        "Latin terms derived from Ancient Greek"
      ],
      "glosses": [
        "Suffix forming nominal compounds (such as anglosaxonicus (“Anglo-Saxon”), from Anglus (“Angle, English”) and saxonicus (“Saxon”))."
      ],
      "links": [
        [
          "anglosaxonicus",
          "anglosaxonicus#Latin"
        ],
        [
          "Anglus",
          "Anglus#Latin"
        ],
        [
          "saxonicus",
          "saxonicus#Latin"
        ]
      ],
      "raw_glosses": [
        "(post-classical Latin) Suffix forming nominal compounds (such as anglosaxonicus (“Anglo-Saxon”), from Anglus (“Angle, English”) and saxonicus (“Saxon”))."
      ],
      "tags": [
        "Latin",
        "morpheme",
        "obsolete"
      ]
    }
  ],
  "word": "-o-"
}