English: alternate seat
Welsh: eilydd
Subject: Gwleidyddiaeth
English definition: Used eg in the following context 'Wales has two full seats and two alternate seats'.
Welsh definition: Yng nghyd-destun seddau aelodau ee 'Wales has two full seats and two alternate seats' / 'Mae gan Gymru ddau aelod llawn a dau eilydd'.. 
Plural: eilyddion