'Caulk' definitions:

Definition of 'caulk'

noun

A waterproof filler and sealant that is used in building and repair to make watertight [syn: caulk, caulking]

verb

Seal with caulking; "caulk the window" [syn: caulk, calk]

From: GCIDE

Caulk \Caulk\, v. t.
1. See Calk, v.. [1913 Webster]
2. to fill in the seams or cracks of, with a waterproof material such as caulk. [PJC]

From: GCIDE

Caulk \Caulk\, n.
1. See Calk. [1913 Webster]
2. a viscous semisolid material of varying composition used to fill in seams of objects which are exposed to water, such as wooden ships or bath tiles; -- called also calk and caulking. After applying in a semisolid form, the material hardens and dries to form a waterproof seal. It is used in the process of caulking. It is sometimes applied together with a rope-like cord to fill larger seams. [PJC]