"relative adverb" meaning in English

{
  "forms": [
    {
      "form": "relative adverbs",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "relative adverb (plural relative adverbs)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with 1 entry",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "topical",
          "langcode": "en",
          "name": "Grammar",
          "orig": "en:Grammar",
          "parents": [
            "Linguistics",
            "Language",
            "Social sciences",
            "Communication",
            "Sciences",
            "Society",
            "All topics",
            "Fundamental"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "An adverb (such as when, where, how, or why) that may begin a relative clause."
      ],
      "id": "en-relative_adverb-en-noun-UUmba7dQ",
      "links": [
        [
          "grammar",
          "grammar"
        ],
        [
          "adverb",
          "adverb"
        ],
        [
          "begin",
          "begin"
        ],
        [
          "relative clause",
          "relative clause"
        ]
      ],
      "raw_glosses": [
        "(grammar) An adverb (such as when, where, how, or why) that may begin a relative clause."
      ],
      "topics": [
        "grammar",
        "human-sciences",
        "linguistics",
        "sciences"
      ]
    }
  ],
  "word": "relative adverb"
}

{
  "forms": [
    {
      "form": "relative adverbs",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "relative adverb (plural relative adverbs)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        "English countable nouns",
        "English entries with incorrect language header",
        "English lemmas",
        "English multiword terms",
        "English nouns",
        "Pages with 1 entry",
        "Pages with entries",
        "en:Grammar"
      ],
      "glosses": [
        "An adverb (such as when, where, how, or why) that may begin a relative clause."
      ],
      "links": [
        [
          "grammar",
          "grammar"
        ],
        [
          "adverb",
          "adverb"
        ],
        [
          "begin",
          "begin"
        ],
        [
          "relative clause",
          "relative clause"
        ]
      ],
      "raw_glosses": [
        "(grammar) An adverb (such as when, where, how, or why) that may begin a relative clause."
      ],
      "topics": [
        "grammar",
        "human-sciences",
        "linguistics",
        "sciences"
      ]
    }
  ],
  "word": "relative adverb"
}