Merriam-Webster Collegiate Dictionary - dado

 I. noun  (plural ~es)  Etymology: Italian, die, plinth  Date: 1664  1.  a. the part of a pedestal of a column above the base  b. the lower part of an interior wall when specially decorated or faced; also the decoration adorning this part of a wall  2. a rectangular groove cut to make a joint in woodworking; specifically one cut across the grain  II. transitive verb  (~ed; ~ing)  Date: 1881  1. to provide with a ~  2.  a. to set into a groove  b. to cut a ~ in (as a plank)