noun that which sheathes.
2. sheathing ·noun the casing or covering of a ship's bottom and sides; the materials for such covering; as, copper sheathing.
3. sheathing (·p.pr. & ·adj) inclosing with a sheath; as, the sheathing leaves of grasses; the sheathing stipules of many polygonaceous plants.
4. sheathing ·noun 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.