Electoral parity refers to a situation in which the ratio of electors to elected members is the same, or nearly the same, in every electoral ward in the principal area.
Mae cydraddoldeb etholiadol yn cyfeirio at sefyllfa lle mae’r gymhareb etholwyr i aelodau etholedig yr un fath, neu bron yr un fath, ym mhob ward etholiadol yn y brif ardal.