Calk \Calk\ (k[add]k), v. t. [imp. &p. p. Calked; p. pr. & vb. n. Calking.]

[Either corrupted fr. F. calfater (cf. Pg. calafetar, Sp. calafetear), fr. Ar. qalafa to fill up crevices with the fibers of palm tree or moss; or fr. OE. cauken to tred, through the French fr. L. calcare, fr. calx heel. Cf. Calk to copy, Inculcate.]

1. To drive tarred oakum into the seams between the planks of (a ship, boat, etc.), to prevent leaking. The calking is completed by smearing the seams with melted pitch.

2. To make an indentation in the edge of a metal plate, as along a seam in a steam boiler or an iron ship, to force the edge of the upper plate hard against the lower and so fill the crevice.

Source: Webster's Revised Unabridged Dictionary (1913)
 

Calking \Calk"ing\, n. The act or process of making seems tight, as in ships, or of furnishing with calks, as a shoe, or copying, as a drawing.

Calking iron, a tool like a chisel, used in calking ships, tightening seams in ironwork, etc.

Their left hand does the calking iron guide. --Dryden.

Source: Webster's Revised Unabridged Dictionary (1913)