Semiconductor industry term used to describe a microprocessor that contains at least the same functions as another, in a package that uses the same pins or electrical connections and signals for the same functions, e.g., ground, power supply, input and outputs and power supply. The term came into use when most microprocessor packaged primarily with dual in-line pin (DIP) connectors surrounding the edge of the package, but has continued to be used as other types of connectors have become commonplace. Strictly speaking it usually implies that the package has the same dimensions and the same type of pin-outs or connectors, e.g., pin-gate-arrays (PGA), Ball Gate Arrays (BGA), Land Gate Arrays (LGA).
In principle pin-compatible components can be swapped for one another without changing changing device operation or design. The term has crept into more general technical usage to describe any electronic or electrical component that can be swapped for another component in a particular device or application without substantial modification.