Caulking

to fill or close seams or crevices of (a tank, window, etc.) in order to make watertight, airtight, etc.
to make (a vessel) watertight by filling the seams between the planks with oakum or other material driven snug.
to fill or close (a seam, joint, etc.), as in a boat.
to drive the edges of (plating) together to prevent leakage.
Also, caulking
[kaw-king] /ˈkɔ kɪŋ/ (Show IPA). a material or substance used for caulking.
Historical Examples

verb
to stop up (cracks, crevices, etc) with a filler
(nautical) to pack (the seams) between the planks of the bottom of (a vessel) with waterproof material to prevent leakage
v.

late 14c., “to stop up crevices or cracks,” from Old North French cauquer, from Late Latin calicare “to stop up chinks with lime,” from Latin calx (2) “lime, limestone” (see chalk). Original sense is nautical, of making ships watertight. Related: Caulked; caulking. As a noun, “caulking material,” by 1980 (caulking in this sense was used from 1743). Related: Caulker.