"registration number" meaning in English

{
  "forms": [
    {
      "form": "registration numbers",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "registration number (plural registration numbers)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "British English",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Entries with translation boxes",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with 1 entry",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Terms with Welsh translations",
          "parents": [],
          "source": "w"
        }
      ],
      "glosses": [
        "Series of letters and numbers on shown on the front and back of a motor vehicle."
      ],
      "id": "en-registration_number-en-noun-g7Uy2xAU",
      "raw_glosses": [
        "(UK) Series of letters and numbers on shown on the front and back of a motor vehicle."
      ],
      "synonyms": [
        {
          "word": "reg"
        },
        {
          "word": "registration"
        }
      ],
      "tags": [
        "UK"
      ],
      "translations": [
        {
          "code": "cy",
          "lang": "Welsh",
          "sense": "Motor vehicle number",
          "tags": [
            "masculine"
          ],
          "word": "rhif cofrestru"
        },
        {
          "code": "cy",
          "lang": "Welsh",
          "sense": "Motor vehicle number",
          "tags": [
            "masculine"
          ],
          "word": "rhif car"
        }
      ]
    }
  ],
  "word": "registration number"
}

{
  "forms": [
    {
      "form": "registration numbers",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "registration number (plural registration numbers)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        "British English",
        "English countable nouns",
        "English entries with incorrect language header",
        "English lemmas",
        "English multiword terms",
        "English nouns",
        "Entries with translation boxes",
        "Pages with 1 entry",
        "Pages with entries",
        "Terms with Welsh translations"
      ],
      "glosses": [
        "Series of letters and numbers on shown on the front and back of a motor vehicle."
      ],
      "raw_glosses": [
        "(UK) Series of letters and numbers on shown on the front and back of a motor vehicle."
      ],
      "synonyms": [
        {
          "word": "reg"
        },
        {
          "word": "registration"
        }
      ],
      "tags": [
        "UK"
      ]
    }
  ],
  "translations": [
    {
      "code": "cy",
      "lang": "Welsh",
      "sense": "Motor vehicle number",
      "tags": [
        "masculine"
      ],
      "word": "rhif cofrestru"
    },
    {
      "code": "cy",
      "lang": "Welsh",
      "sense": "Motor vehicle number",
      "tags": [
        "masculine"
      ],
      "word": "rhif car"
    }
  ],
  "word": "registration number"
}