An Intel microprocessor that uses explicitly parallel instruction set computing and 64-bit memory addressing. "Itanium-based" refers to systems or platforms that are based on the Itanium processor. "Itanium2-based" refers to systems or platforms that are based on the Itanium2 processor. "Itanium architecture-based" refers to systems or platforms that are based on the Itanium and Itanium2 processors.