(1):

(p. pr. & vb. n.) of Tub

(2):

(n.) The forming of a tub; also, collectively, materials for tubs.

(3):

(n.) A lining of timber or metal around the shaft of a mine; especially, a series of cast-iron cylinders bolted together, used to enable those who sink a shaft to penetrate quicksand, water, etc., with safety.