In mendelian genetics, those genetic characteristics that are expressed in an organism are said to be

Genetic cgaracters that are expressed in an organisms known as dominant characters.

Explanation:

Mendel introduced the concept of dominance and recessiveness about the expression of genes. He noticed that there are some characters which are expressed in offsprings and some characters that are not expressed in an organisms. Those genes which show themselves in offsprings are known as dominant genes.

Example:

Tall plant height is a dominant character over short plant height.