ASIC is an acronym of Application Specific Integrated Circuit.
ASIC is a computer chip specifically created to execute one task. An example of one such model is an ASIC miner created to ONLY process SHA-256, which is the problem offered by the Bitcoin Blockchain to mine new coins. There are also ASIC’s for scrypt which specifically solves the mathematical code for some Altcoins such as Litecoin.
ASIC mining is one of the main forms of mining together with GPU mining, as they are much more efficient than mining using normal computers.
Though, in recent years there has been a good amount of dialogue surrounding the longevity of mining this way and we’ve even seen coins making it so that it’s impossible to mine with an ASIC replaced with PoS, DPos, PoB, PoHe and others.