Gwill (gender unknown)
(with) definite article: ?reed consisting of a base (the Body) with a vibrating blade (the Tongue)
From "quill", after the material traditionally used.
Traditionally made from goose quill; Nowadays [i.e. late 20th century; ws] of Spanish cane (Arundo donax) or elder (Bour-tree; Sambucus nigra).
Garvin, Wilbert: The Irish bagpipes: their construction and maintenance [Belfast 1978, Blackstaff Press]. Foreword by Breandán Breathnach. Kells, 1988 (2), p.25.