Is plinth wall a load bearing wall?

Lath and plaster is just an old type of wall finish. Like drywall is a wall finish. What the wall is constructed of underneath the lath and plaster and where it is placed in the building determine if it is load bearing or not. A lath and plaster wall could be load bearing or it might not be. IF it is an outside wall, it most certainly is load bearing. other than that, the best way to figure it out is to have a structural engineer tell you wether it is or not. Even if it is load bearing it may be possible to remove it if a beam is put up in place of the wall. Really, the best and safest way to decide is to have a engineer look at it.