I've never heard of subaxle myself, but the subaru tech that looked at my mom's wrx told her that they needed to replace a strut and a subaxle after a little run-in with a curb. Is this the halfshaft thats between the cv joints? thats the only thing i thought it could be.

 

he was probably talking about a stub axle, and just not speaking clearly. i believe that stub axles are essentially the same as halfshafts.