caulk / kôk/ (also calk) • n. (also caulk·ing) a waterproof filler and sealant, used in building work and repairs.• v. [tr.] seal (a gap or seam) with such a substance. ∎  stop up (the seams of a boat) with oakum and waterproofing material, or by driving plate-junctions together; make (a boat) watertight by this method.DERIVATIVES: caulk·er n.

caulk XV. — OF. cauquer, caukier, north. var. of OF. cauchier tread, press with force :- L. calcāre tread, press, f. calx, calc- heel.