[mor.gan] n [Thomas Hunt Morgan] (1919) 1: a unit of inferred distance between genes on a chromosome that is used in constructing genetic maps and is equal to the distance for which the frequency of crossing over between specific pairs of genes is 100 percent
2: centimorgan Mor.gan n [Justin Morgan d. 1798 Am. teacher] (1841): any of an American breed of light strong horses originated in Vermont from the progeny of one prepotent stallion of uncertain ancestry