"тресяло" meaning in Bulgarian

{
  "forms": [
    {
      "form": "треся́ло",
      "tags": [
        "canonical"
      ]
    },
    {
      "form": "tresjálo",
      "tags": [
        "romanization"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "треся́ло"
      },
      "expansion": "треся́ло • (tresjálo)",
      "name": "bg-part form"
    }
  ],
  "lang": "Bulgarian",
  "lang_code": "bg",
  "pos": "verb",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "Bulgarian entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        }
      ],
      "form_of": [
        {
          "extra": "tresá",
          "word": "треса́"
        }
      ],
      "glosses": [
        "neuter singular past active imperfect participle of треса́ (tresá)"
      ],
      "id": "en-тресяло-bg-verb-pZxKOXxd",
      "links": [
        [
          "треса́",
          "треса#Bulgarian"
        ]
      ],
      "tags": [
        "active",
        "form-of",
        "imperfect",
        "neuter",
        "participle",
        "past",
        "singular"
      ]
    }
  ],
  "sounds": [
    {
      "ipa": "[trɛˈsʲa̟ɫo]"
    }
  ],
  "word": "тресяло"
}

{
  "forms": [
    {
      "form": "треся́ло",
      "tags": [
        "canonical"
      ]
    },
    {
      "form": "tresjálo",
      "tags": [
        "romanization"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "треся́ло"
      },
      "expansion": "треся́ло • (tresjálo)",
      "name": "bg-part form"
    }
  ],
  "lang": "Bulgarian",
  "lang_code": "bg",
  "pos": "verb",
  "senses": [
    {
      "categories": [
        "Bulgarian entries with incorrect language header",
        "Bulgarian non-lemma forms",
        "Bulgarian participle forms",
        "Bulgarian terms with IPA pronunciation",
        "Bulgarian verb forms"
      ],
      "form_of": [
        {
          "extra": "tresá",
          "word": "треса́"
        }
      ],
      "glosses": [
        "neuter singular past active imperfect participle of треса́ (tresá)"
      ],
      "links": [
        [
          "треса́",
          "треса#Bulgarian"
        ]
      ],
      "tags": [
        "active",
        "form-of",
        "imperfect",
        "neuter",
        "participle",
        "past",
        "singular"
      ]
    }
  ],
  "sounds": [
    {
      "ipa": "[trɛˈsʲa̟ɫo]"
    }
  ],
  "word": "тресяло"
}