Dado \Da"do\, n.; pl. Dadoes. [It. dado die, cube, pedestal; of the same origin as E. die, n. See Die, n.]

(Arch.)
   (a) That part of a pedestal included between the base and the cornice (or surbase); the die. See Illust. of Column. Hence:
   (b) In any wall, that part of the basement included between the base and the base course. See Base course, under Base.
   (c) In interior decoration, the lower part of the wall of an apartment when adorned with moldings, or otherwise specially decorated.

Source: Webster's Revised Unabridged Dictionary (1913)