"alpha channel" meaning in English

{
  "etymology_text": "Coined by Alvy Ray Smith and Ed Catmull in the 1970s. Smith writes: \"We called it that because of the classic linear interpolation formula αA+(1-α)B that uses the Greek letter α (alpha) to control the amount of interpolation between, in this case, two images A and B\". That is, when compositing image A atop image B, the value of α in the formula is A's alpha channel.",
  "forms": [
    {
      "form": "alpha channels",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "alpha channel (plural alpha channels)",
      "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"
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          "source": "w"
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        },
        {
          "kind": "topical",
          "langcode": "en",
          "name": "Computer graphics",
          "orig": "en:Computer graphics",
          "parents": [
            "Computing",
            "Technology",
            "All topics",
            "Fundamental"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "A numerical value specifying a level of translucency to be applied to a colour."
      ],
      "id": "en-alpha_channel-en-noun-T80fpKh8",
      "links": [
        [
          "computer graphics",
          "computer graphics"
        ],
        [
          "numerical",
          "numerical"
        ],
        [
          "value",
          "value"
        ],
        [
          "translucency",
          "translucency"
        ],
        [
          "colour",
          "colour"
        ]
      ],
      "raw_glosses": [
        "(computer graphics) A numerical value specifying a level of translucency to be applied to a colour."
      ],
      "topics": [
        "computer-graphics",
        "computing",
        "engineering",
        "mathematics",
        "natural-sciences",
        "physical-sciences",
        "sciences"
      ],
      "translations": [
        {
          "code": "fi",
          "lang": "Finnish",
          "sense": "numeric value",
          "word": "alfakanava"
        },
        {
          "code": "pt",
          "lang": "Portuguese",
          "sense": "numeric value",
          "tags": [
            "masculine"
          ],
          "word": "canal alfa"
        }
      ],
      "wikipedia": [
        "Alvy Ray Smith",
        "Ed Catmull",
        "alpha channel"
      ]
    }
  ],
  "word": "alpha channel"
}

{
  "etymology_text": "Coined by Alvy Ray Smith and Ed Catmull in the 1970s. Smith writes: \"We called it that because of the classic linear interpolation formula αA+(1-α)B that uses the Greek letter α (alpha) to control the amount of interpolation between, in this case, two images A and B\". That is, when compositing image A atop image B, the value of α in the formula is A's alpha channel.",
  "forms": [
    {
      "form": "alpha channels",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "alpha channel (plural alpha channels)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
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        "en:Computer graphics"
      ],
      "glosses": [
        "A numerical value specifying a level of translucency to be applied to a colour."
      ],
      "links": [
        [
          "computer graphics",
          "computer graphics"
        ],
        [
          "numerical",
          "numerical"
        ],
        [
          "value",
          "value"
        ],
        [
          "translucency",
          "translucency"
        ],
        [
          "colour",
          "colour"
        ]
      ],
      "raw_glosses": [
        "(computer graphics) A numerical value specifying a level of translucency to be applied to a colour."
      ],
      "topics": [
        "computer-graphics",
        "computing",
        "engineering",
        "mathematics",
        "natural-sciences",
        "physical-sciences",
        "sciences"
      ],
      "wikipedia": [
        "Alvy Ray Smith",
        "Ed Catmull",
        "alpha channel"
      ]
    }
  ],
  "translations": [
    {
      "code": "fi",
      "lang": "Finnish",
      "sense": "numeric value",
      "word": "alfakanava"
    },
    {
      "code": "pt",
      "lang": "Portuguese",
      "sense": "numeric value",
      "tags": [
        "masculine"
      ],
      "word": "canal alfa"
    }
  ],
  "word": "alpha channel"
}