alpha channel
Word Rarity
Uncommon
Frequency: 4.15 in modern English
22
Scrabble Score
12
Letters
3
Syllables
7
Unique Chars
Meaning
noun
A numerical value specifying a level of translucency to be applied to a colour.
Etymology
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.