[Dolphinsiu]

I have read from regioselectivity is resulted from majority of regioisomers which is caused by unsymmetry.

H    R                     H     R       R      H
C = C  +  X - Y -->   C --- C  +   C  --- C
                             X     Y      Y      X

But why we have been taught regioselectivity in nitration of naphthalene? but not call stereoselectivity in nitration of naphthalene?
Are all regioisomers belongs to stereoisomer?