Instruction Set Architecture (ISA) is also a common name for it. That and tons of linux distributions and people refer to it as "arch" or "architecture". GNU coreutils even has a program named arch that prints out the "machine hardware name" (ew...).
The fact is lots of people call it architecture and it can reasonably be called architecture in the given context. I'll allow it!
Not denying it's important to know the difference, though!