"-oi" meaning in English

{
  "etymology_templates": [
    {
      "args": {
        "1": "en",
        "2": "grc",
        "3": "-οι"
      },
      "expansion": "Ancient Greek -οι (-oi)",
      "name": "bor"
    }
  ],
  "etymology_text": "From the Ancient Greek -οι (-oi), the second-declension masculine nominative plural case ending — the plural form of -ος (-os); compare the equivalents of the Latin second declension (-us → -ī), with which the Grecian case endings are usually substituted in English words, especially in the plural.",
  "head_templates": [
    {
      "args": {
        "1": "en",
        "2": "suffix"
      },
      "expansion": "-oi",
      "name": "head"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "suffix",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "English plurals in -oi with singular in -os",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with 2 entries",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w"
        },
        {
          "_dis": "65 14 5 17",
          "kind": "other",
          "name": "Pages with 2 entries",
          "parents": [],
          "source": "w+disamb"
        },
        {
          "_dis": "64 18 4 15",
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w+disamb"
        }
      ],
      "derived": [
        {
          "word": "Melanochroi"
        },
        {
          "word": "Melanoi"
        },
        {
          "word": "Xanthochroi"
        },
        {
          "word": "Xanthomelanoi"
        }
      ],
      "form_of": [
        {
          "word": "-os"
        }
      ],
      "glosses": [
        "plural of -os"
      ],
      "id": "en--oi-en-suffix-CwyBqOTq",
      "links": [
        [
          "-os",
          "-os#English"
        ]
      ],
      "tags": [
        "form-of",
        "morpheme",
        "plural"
      ]
    }
  ],
  "sounds": [
    {
      "enpr": "-oi",
      "tags": [
        "Received-Pronunciation"
      ]
    },
    {
      "ipa": "/-ɔɪ/",
      "tags": [
        "Received-Pronunciation"
      ]
    }
  ],
  "word": "-oi"
}

{
  "categories": [
    "Pages with 2 entries",
    "Pages with entries"
  ],
  "derived": [
    {
      "word": "Melanochroi"
    },
    {
      "word": "Melanoi"
    },
    {
      "word": "Xanthochroi"
    },
    {
      "word": "Xanthomelanoi"
    }
  ],
  "etymology_templates": [
    {
      "args": {
        "1": "en",
        "2": "grc",
        "3": "-οι"
      },
      "expansion": "Ancient Greek -οι (-oi)",
      "name": "bor"
    }
  ],
  "etymology_text": "From the Ancient Greek -οι (-oi), the second-declension masculine nominative plural case ending — the plural form of -ος (-os); compare the equivalents of the Latin second declension (-us → -ī), with which the Grecian case endings are usually substituted in English words, especially in the plural.",
  "head_templates": [
    {
      "args": {
        "1": "en",
        "2": "suffix"
      },
      "expansion": "-oi",
      "name": "head"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "suffix",
  "senses": [
    {
      "categories": [
        "English entries with incorrect language header",
        "English lemmas",
        "English plurals in -oi with singular in -os",
        "English suffixes",
        "English terms borrowed from Ancient Greek",
        "English terms derived from Ancient Greek",
        "Pages with 2 entries",
        "Pages with entries"
      ],
      "form_of": [
        {
          "word": "-os"
        }
      ],
      "glosses": [
        "plural of -os"
      ],
      "links": [
        [
          "-os",
          "-os#English"
        ]
      ],
      "tags": [
        "form-of",
        "morpheme",
        "plural"
      ]
    }
  ],
  "sounds": [
    {
      "enpr": "-oi",
      "tags": [
        "Received-Pronunciation"
      ]
    },
    {
      "ipa": "/-ɔɪ/",
      "tags": [
        "Received-Pronunciation"
      ]
    }
  ],
  "word": "-oi"
}