An ASIC is a computer chip built to do one job very well, instead of a general chip that can run many kinds of programs. The letters stand for Application-Specific Integrated Circuit: “application-specific” means “made for one use,” and “integrated circuit” is the technical name for a chip. Phone makers, car companies, and some coin-mining machines use them because a chip that only does one thing can be smaller, faster, or use less power. It is an engineers’ word. People in that world often say it as a word, like “ay-sick,” not as four letters. Ordinary English almost never needs it unless you are reading tech news.