Webster's Revised Unabridged Dictionary · 1913

Inclosing with a sheath; as, the sheathing leaves of grasses; the sheathing stipules of many polygonaceous plants.

(Architecture) That which sheathes.

(Architecture) The casing or covering of a ship's bottom and sides; the materials for such covering; as, copper sheathing.

(Architecture) The first covering of boards on the outside wall of a frame house or on a timber roof; also, the material used for covering; ceiling boards in general.