"-ad" meaning in Old Irish

{
  "descendants": [
    {
      "lang": "Irish",
      "lang_code": "ga",
      "word": "-adh"
    },
    {
      "lang": "Manx",
      "lang_code": "gv",
      "word": "-ey"
    },
    {
      "lang": "Scottish Gaelic",
      "lang_code": "gd",
      "word": "-adh"
    }
  ],
  "etymology_number": 1,
  "etymology_templates": [
    {
      "args": {
        "1": "sga",
        "2": "cel-pro",
        "3": "*-tus"
      },
      "expansion": "Proto-Celtic *-tus",
      "name": "der"
    }
  ],
  "etymology_text": "From the various thematic vowels of verb stems plus Proto-Celtic *-tus, i.e. from *-atus, *-ātus, *-etus, and *-ītus.",
  "forms": [
    {
      "form": "-ed",
      "tags": [
        "alternative"
      ]
    },
    {
      "form": "-ud",
      "raw_tags": [
        "with A II verbs"
      ],
      "tags": [
        "alternative",
        "often"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "sga",
        "2": "suffix",
        "3": "forms the genitive singular in <i class=\"Latn mention nowrap\" lang=\"sga\">-(a)tho</i>",
        "cat2": "noun-forming suffixes",
        "g": "m"
      },
      "expansion": "-ad m (forms the genitive singular in -(a)tho)",
      "name": "head"
    }
  ],
  "lang": "Old Irish",
  "lang_code": "sga",
  "pos": "suffix",
  "senses": [
    {
      "categories": [
        {
          "_dis": "1 9 2 6 6 10 26 7 2 2 6 15 7",
          "kind": "other",
          "name": "Pages using catfix",
          "parents": [],
          "source": "w+disamb"
        },
        {
          "_dis": "1 6 1 5 5 8 23 2 11 2 5 1 3 2 1 5 13 6",
          "kind": "other",
          "name": "Pages with 10 entries",
          "parents": [],
          "source": "w+disamb"
        },
        {
          "_dis": "0 4 1 5 6 8 26 1 12 1 5 1 2 1 1 6 14 7",
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w+disamb"
        },
        {
          "_dis": "44 8 23 7 12 6",
          "kind": "other",
          "name": "Old Irish entries with incorrect language header",
          "parents": [],
          "source": "w+disamb"
        }
      ],
      "glosses": [
        "suffix forming verbal nouns"
      ],
      "id": "en--ad-sga-suffix-17f7R~O2",
      "tags": [
        "masculine",
        "morpheme"
      ]
    }
  ],
  "word": "-ad"
}

{
  "etymology_number": 2,
  "etymology_templates": [
    {
      "args": {
        "1": "sga",
        "2": "cel-pro",
        "3": "*-to"
      },
      "expansion": "Proto-Celtic *-to",
      "name": "der"
    }
  ],
  "etymology_text": "From the various thematic vowels of verb stems plus Proto-Celtic *-to, i.e. from *-ato, *-āto, *-eto, and *-īto.",
  "forms": [
    {
      "form": "-ed",
      "tags": [
        "alternative"
      ]
    },
    {
      "form": "-ud",
      "raw_tags": [
        "with A II verbs"
      ],
      "tags": [
        "alternative",
        "often"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "sga",
        "2": "suffix",
        "cat2": "inflectional suffixes"
      },
      "expansion": "-ad",
      "name": "head"
    }
  ],
  "lang": "Old Irish",
  "lang_code": "sga",
  "pos": "suffix",
  "senses": [
    {
      "glosses": [
        "suffix forming the third-person singular imperative form"
      ],
      "id": "en--ad-sga-suffix-jmfcrfeo",
      "tags": [
        "morpheme"
      ]
    },
    {
      "glosses": [
        "suffix forming the third-person singular imperfect indicative form"
      ],
      "id": "en--ad-sga-suffix-KhNb7sZY",
      "tags": [
        "morpheme"
      ]
    },
    {
      "glosses": [
        "suffix forming the third-person singular past subjunctive form"
      ],
      "id": "en--ad-sga-suffix-u5joIosR",
      "tags": [
        "morpheme"
      ]
    },
    {
      "glosses": [
        "suffix forming the third-person singular conditional form of reduplicated and ē-future stems"
      ],
      "id": "en--ad-sga-suffix-TswY1Qja",
      "tags": [
        "morpheme"
      ]
    },
    {
      "glosses": [
        "suffix forming the singular passive conjunct preterite form of s-preterite stems"
      ],
      "id": "en--ad-sga-suffix-tpUjW9ML",
      "tags": [
        "morpheme"
      ]
    }
  ],
  "word": "-ad"
}

{
  "categories": [
    "Old Irish entries with incorrect language header",
    "Old Irish inflectional suffixes",
    "Old Irish lemmas",
    "Old Irish masculine suffixes",
    "Old Irish noun-forming suffixes",
    "Old Irish suffixes",
    "Old Irish terms derived from Proto-Celtic",
    "Pages using catfix",
    "Pages with 10 entries",
    "Pages with entries"
  ],
  "descendants": [
    {
      "lang": "Irish",
      "lang_code": "ga",
      "word": "-adh"
    },
    {
      "lang": "Manx",
      "lang_code": "gv",
      "word": "-ey"
    },
    {
      "lang": "Scottish Gaelic",
      "lang_code": "gd",
      "word": "-adh"
    }
  ],
  "etymology_number": 1,
  "etymology_templates": [
    {
      "args": {
        "1": "sga",
        "2": "cel-pro",
        "3": "*-tus"
      },
      "expansion": "Proto-Celtic *-tus",
      "name": "der"
    }
  ],
  "etymology_text": "From the various thematic vowels of verb stems plus Proto-Celtic *-tus, i.e. from *-atus, *-ātus, *-etus, and *-ītus.",
  "forms": [
    {
      "form": "-ed",
      "tags": [
        "alternative"
      ]
    },
    {
      "form": "-ud",
      "raw_tags": [
        "with A II verbs"
      ],
      "tags": [
        "alternative",
        "often"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "sga",
        "2": "suffix",
        "3": "forms the genitive singular in <i class=\"Latn mention nowrap\" lang=\"sga\">-(a)tho</i>",
        "cat2": "noun-forming suffixes",
        "g": "m"
      },
      "expansion": "-ad m (forms the genitive singular in -(a)tho)",
      "name": "head"
    }
  ],
  "lang": "Old Irish",
  "lang_code": "sga",
  "pos": "suffix",
  "senses": [
    {
      "glosses": [
        "suffix forming verbal nouns"
      ],
      "tags": [
        "masculine",
        "morpheme"
      ]
    }
  ],
  "word": "-ad"
}

{
  "categories": [
    "Old Irish entries with incorrect language header",
    "Old Irish inflectional suffixes",
    "Old Irish lemmas",
    "Old Irish suffixes",
    "Old Irish terms derived from Proto-Celtic",
    "Pages with 10 entries",
    "Pages with entries"
  ],
  "etymology_number": 2,
  "etymology_templates": [
    {
      "args": {
        "1": "sga",
        "2": "cel-pro",
        "3": "*-to"
      },
      "expansion": "Proto-Celtic *-to",
      "name": "der"
    }
  ],
  "etymology_text": "From the various thematic vowels of verb stems plus Proto-Celtic *-to, i.e. from *-ato, *-āto, *-eto, and *-īto.",
  "forms": [
    {
      "form": "-ed",
      "tags": [
        "alternative"
      ]
    },
    {
      "form": "-ud",
      "raw_tags": [
        "with A II verbs"
      ],
      "tags": [
        "alternative",
        "often"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "sga",
        "2": "suffix",
        "cat2": "inflectional suffixes"
      },
      "expansion": "-ad",
      "name": "head"
    }
  ],
  "lang": "Old Irish",
  "lang_code": "sga",
  "pos": "suffix",
  "senses": [
    {
      "glosses": [
        "suffix forming the third-person singular imperative form"
      ],
      "tags": [
        "morpheme"
      ]
    },
    {
      "glosses": [
        "suffix forming the third-person singular imperfect indicative form"
      ],
      "tags": [
        "morpheme"
      ]
    },
    {
      "glosses": [
        "suffix forming the third-person singular past subjunctive form"
      ],
      "tags": [
        "morpheme"
      ]
    },
    {
      "glosses": [
        "suffix forming the third-person singular conditional form of reduplicated and ē-future stems"
      ],
      "tags": [
        "morpheme"
      ]
    },
    {
      "glosses": [
        "suffix forming the singular passive conjunct preterite form of s-preterite stems"
      ],
      "tags": [
        "morpheme"
      ]
    }
  ],
  "word": "-ad"
}

{
  "called_from": "form_descriptions/1698",
  "msg": "unrecognized head form: forms the genitive singular in -(a)tho",
  "path": [
    "-ad"
  ],
  "section": "Old Irish",
  "subsection": "suffix",
  "title": "-ad",
  "trace": ""
}