Definify.com
Webster 1913 Edition
Rubican
Ru′bi-can
,Adj.
[F.]
Colored a prevailing red, bay, or black, with flecks of white or gray especially on the flanks; – said of horses.
Smart.
Webster 1828 Edition
Rubican
RU'BICAN
,Adj.
Rubican color of a horse, is a bay, sorrel or black, with a light gray or white upon the flanks, but the gray or white not predominant there.