"trifocals" meaning in English

{
  "etymology_text": "From tri- + focal (see focus). Coined by John Isaac Hawkins, their inventor, in 1826.",
  "head_templates": [
    {
      "args": {
        "1": "p"
      },
      "expansion": "trifocals pl (plural only)",
      "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": "English pluralia tantum",
          "parents": [
            "Pluralia tantum",
            "Nouns",
            "Lemmas"
          ],
          "source": "w"
        },
        {
          "kind": "topical",
          "langcode": "en",
          "name": "Glasses",
          "orig": "en:Glasses",
          "parents": [
            "Eyewear",
            "Clothing",
            "Eye",
            "Vision",
            "Human",
            "Face",
            "Senses",
            "All topics",
            "Head and neck",
            "Perception",
            "Fundamental",
            "Body parts",
            "Body",
            "Anatomy",
            "Biology",
            "Medicine",
            "Sciences"
          ],
          "source": "w"
        },
        {
          "kind": "topical",
          "langcode": "en",
          "name": "Optics",
          "orig": "en:Optics",
          "parents": [
            "Physics",
            "Sciences",
            "All topics",
            "Fundamental"
          ],
          "source": "w"
        },
        {
          "kind": "topical",
          "langcode": "en",
          "name": "Three",
          "orig": "en:Three",
          "parents": [
            "Numbers",
            "All topics",
            "Terms by semantic function",
            "Fundamental"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "Spectacles with corrective lenses that have three different powers per eye."
      ],
      "id": "en-trifocals-en-noun-KcYtJEAk",
      "links": [
        [
          "optics",
          "optics"
        ],
        [
          "Spectacles",
          "spectacles"
        ],
        [
          "corrective",
          "corrective"
        ],
        [
          "lenses",
          "lenses"
        ],
        [
          "different",
          "different"
        ],
        [
          "power",
          "power"
        ],
        [
          "eye",
          "eye"
        ]
      ],
      "raw_glosses": [
        "(optics) Spectacles with corrective lenses that have three different powers per eye."
      ],
      "related": [
        {
          "word": "bifocals"
        },
        {
          "word": "trifocal"
        }
      ],
      "tags": [
        "plural",
        "plural-only"
      ],
      "topics": [
        "engineering",
        "natural-sciences",
        "optics",
        "physical-sciences",
        "physics"
      ],
      "translations": [
        {
          "code": "fi",
          "lang": "Finnish",
          "sense": "type of spectacles",
          "word": "kolmiteholasit"
        }
      ],
      "wikipedia": [
        "trifocals"
      ]
    }
  ],
  "word": "trifocals"
}

{
  "etymology_text": "From tri- + focal (see focus). Coined by John Isaac Hawkins, their inventor, in 1826.",
  "head_templates": [
    {
      "args": {
        "1": "p"
      },
      "expansion": "trifocals pl (plural only)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "related": [
    {
      "word": "bifocals"
    },
    {
      "word": "trifocal"
    }
  ],
  "senses": [
    {
      "categories": [
        "English 3-syllable words",
        "English entries with incorrect language header",
        "English lemmas",
        "English nouns",
        "English pluralia tantum",
        "en:Glasses",
        "en:Optics",
        "en:Three"
      ],
      "glosses": [
        "Spectacles with corrective lenses that have three different powers per eye."
      ],
      "links": [
        [
          "optics",
          "optics"
        ],
        [
          "Spectacles",
          "spectacles"
        ],
        [
          "corrective",
          "corrective"
        ],
        [
          "lenses",
          "lenses"
        ],
        [
          "different",
          "different"
        ],
        [
          "power",
          "power"
        ],
        [
          "eye",
          "eye"
        ]
      ],
      "raw_glosses": [
        "(optics) Spectacles with corrective lenses that have three different powers per eye."
      ],
      "tags": [
        "plural",
        "plural-only"
      ],
      "topics": [
        "engineering",
        "natural-sciences",
        "optics",
        "physical-sciences",
        "physics"
      ],
      "wikipedia": [
        "trifocals"
      ]
    }
  ],
  "translations": [
    {
      "code": "fi",
      "lang": "Finnish",
      "sense": "type of spectacles",
      "word": "kolmiteholasit"
    }
  ],
  "word": "trifocals"
}