from
The Collaborative International Dictionary of English v.0.48
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. Daedal