Genotype refers to the genetic constitution (the genome ) of a cell, an individual or an organism. Also, Genotype refers to the genetic form or constitution of a person as determined b y heredity; the total composite of hereditary instructions coded in the genes at the moment of conception.

The genotype of a person is her or his specific genetic makeup. It can pertain to all genes or to a specific gene. The Genotype is distinct from its expressed features, or phenotype.

By contrast, the phenotype results from the interaction between the genotype and the environment. It is the composite of the characteristics shown by the cell, individual or organism under a particular set of environmental conditions.
Other /More definition:
genotype refers to specific genetic makeup of an individual.
Other /More definition:
genotype refers to a person's specific genetic makeup.