No, it’s Windows NT, for Advanced RISC Machines—somewhat similar to Windows NT 3.x/4.0—there were several versions available: MIPS, AlphaAXP (one of the earliest 64-bit architectures), PowerPC.
As well as Intel, of course.
When Windows 2000 rolled around, MS got rid of the other builds.
Obviously, there was no restriction on creating Windows NT for other CPUs—they were already working on the IA64 version (which would become Windows .NET Server 2003)