Why do Linux world use the term i386 instead of x86?

I see the term **i386** instead of **x86** in many places related to Linux. As of my knowledge, **they are not interchangeable**. x86 is a family of instruction set architectures where i386 is a specific one of the x86 processors. But why do Linux world uses the term i386 instead of x86 ?
References:
x86 | Wikipeadia
Intel 80386 | Wikipeadia