indeclinable intensive particle: “just so, certainly, indeed” only in phrase “evaṃ byā kho” Vin.ii.26; Vin.iv.134 = DN-a.i.27; MN.i.130 (evaṃ vyā kho ti evaṃ viya kho C.), MN.i.257.

distorted fr. iva = eva, with metathesis & diaeresis *veyya → *veyyā → *vyā → byā