"rad⋅s⁻²" meaning in Conventions internationales

{
  "categories": [
    {
      "kind": "other",
      "name": "Convention internationale des unités de mesure",
      "parents": [],
      "source": "w"
    },
    {
      "kind": "other",
      "name": "Symboles en conventions internationales",
      "parents": [],
      "source": "w"
    },
    {
      "kind": "other",
      "name": "Conventions internationales",
      "orig": "conventions internationales",
      "parents": [],
      "source": "w"
    }
  ],
  "lang": "Conventions internationales",
  "lang_code": "conv",
  "pos": "symbol",
  "pos_title": "Symbole",
  "related": [
    {
      "word": "rad/s²"
    }
  ],
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "Lexique en conventions internationales de la métrologie",
          "parents": [],
          "source": "w"
        }
      ],
      "glosses": [
        "Symbole du radian par seconde carrée, unité de mesure de l'accélération angulaire du Système international (SI)."
      ],
      "id": "fr-rad⋅s⁻²-conv-symbol-ddvtSyti",
      "topics": [
        "metrology"
      ]
    }
  ],
  "word": "rad⋅s⁻²"
}

{
  "categories": [
    "Convention internationale des unités de mesure",
    "Symboles en conventions internationales",
    "conventions internationales"
  ],
  "lang": "Conventions internationales",
  "lang_code": "conv",
  "pos": "symbol",
  "pos_title": "Symbole",
  "related": [
    {
      "word": "rad/s²"
    }
  ],
  "senses": [
    {
      "categories": [
        "Lexique en conventions internationales de la métrologie"
      ],
      "glosses": [
        "Symbole du radian par seconde carrée, unité de mesure de l'accélération angulaire du Système international (SI)."
      ],
      "topics": [
        "metrology"
      ]
    }
  ],
  "word": "rad⋅s⁻²"
}