/kawk/ , v.t.
1. to fill or close seams or crevices of (a tank, window, etc.) in order to make watertight, airtight, etc.
2. to make (a vessel) watertight by filling the seams between the planks with oakum or other material driven snug.
3. to fill or close (a seam, joint, etc.), as in a boat.
4. to drive the edges of (plating) together to prevent leakage.
n.
5. Also, caulking /kaw"king/ . a material or substance used for caulking.
Also, calk .
[ 1350-1400; calcare to trample, tread on (v. deriv. of calx heel), conflated with ME cauken cauquer to trample ]