Application Specific Integrated Circuit

microchip that is customized for use in a particular application (Computers)

An application-specific integrated circuit (ASIC) is an integrated circuit (IC) customized for a particular use, rather than intended for general-purpose use. For example, a chip designed solely to run a cell phone is an ASIC. In contrast, the 7400 series and 4000 series integrated circuits are logic building blocks that can be wired together for use in many different applications. Intermediate between ASICs and standard products are application specific standard products (ASSPs).
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<hardware> (ASIC) An integrated circuit designed to perform a particular function by defining the interconnection of a set of basic circuit building blocks drawn from a library provided by the circuit manufacturer.
(1995-02-15)

a proprietary integrated circuit designed to meet a particular customers specific application requirements.