Like he said, people throw the term around to indicate the swap. I "Solid Axle Swapped" my 1987 4runner, which originally had "Independent Front Suspension" (IFS). Rarely I'll see people abbreviate SFA to indicate they have a solid front axle, usually when it was stock.
These 4runners had solid front axles through 1985, and had independent front suspension forever after. So people with 86 and newer models may indicate they want to "SAS it" to get super rock crawl mode.