A character is a property of an organism, for example, the color of a flower. 

While genes are usually thought to entail some direct causal consequence in the expression of a character, a central tenet of genetics is that a mutant locus or the normal allele does not "control a character," but is only a differential. The production of a character involves many genes. 

The move to the view that organisms have individual characters, whose variations within a population are important objects of study, was an important shift in nineteenth-century biology. Characters are named to express likeness among entities, but by recognizing likeness it becomes possible to describe variation.