"magnētiskais lauks" meaning in Letton

{
  "categories": [
    {
      "kind": "other",
      "name": "Genres manquants en letton",
      "parents": [],
      "source": "w"
    },
    {
      "kind": "other",
      "name": "Noms communs en letton",
      "parents": [],
      "source": "w"
    },
    {
      "kind": "other",
      "name": "Letton",
      "orig": "letton",
      "parents": [],
      "source": "w"
    }
  ],
  "lang": "Letton",
  "lang_code": "lv",
  "pos": "noun",
  "pos_title": "Nom commun",
  "raw_tags": [
    "genre à préciser : {{m}}, {{f}}, {{mf}}, {{n}} ?"
  ],
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "Lexique en letton de la physique",
          "parents": [],
          "source": "w"
        }
      ],
      "glosses": [
        "Champ magnétique."
      ],
      "id": "fr-magnētiskais_lauks-lv-noun-6SozOqRK",
      "tags": [
        "physical"
      ]
    }
  ],
  "word": "magnētiskais lauks"
}

{
  "categories": [
    "Genres manquants en letton",
    "Noms communs en letton",
    "letton"
  ],
  "lang": "Letton",
  "lang_code": "lv",
  "pos": "noun",
  "pos_title": "Nom commun",
  "raw_tags": [
    "genre à préciser : {{m}}, {{f}}, {{mf}}, {{n}} ?"
  ],
  "senses": [
    {
      "categories": [
        "Lexique en letton de la physique"
      ],
      "glosses": [
        "Champ magnétique."
      ],
      "tags": [
        "physical"
      ]
    }
  ],
  "word": "magnētiskais lauks"
}