Bag
Usually protected by a decorative velvet or cloth cover (with trimmings).
Traditionally made of basil [a soft dry-cured sheepskin, also called "basan"]), nowadays [i.e. late 20th century; ws] often of tanned leather or alternative material.
Garvin, Wilbert: The Irish bagpipes: their construction and maintenance [Belfast 1978, Blackstaff Press]. Foreword by Breandán Breathnach. Kells, 1988 (2), p.2, 5 (basil).