In what context?

Triscend have been known to refer to the 8032 core in their E5 as a "Turbo 8032" and, more specifically, as an "Enhanced, high-performance, 8051-based microcontroller"
http://www.triscend.com/products/e5.htm

So, unless you're looking at a specific usage, it's just going to mean some sort of "enhanced" (usually "faster") 8032.
I'm sure if it was '251-based, they'd say so.