A person has a disability if s/he has a physical or mental impairment which has a substantial and long-term adverse effect on that person's ability to carry out normal day-to-day activities.
Mae gan berson anabledd os oes nam corfforol neu feddyliol arno sy’n cael effaith anffafriol sylweddol a hirdymor ar allu’r person hwnnw i gyflawni gweithgareddau beunyddiol arferol.