What does an organism's phenotype describe?

It describes about the physical appearance of a trait

Explanation:

The allelic combination of the organism is known as its genotype. The genotype is responsible for determining the traits (phenotype) of the organism. However, these traits are not solely determined by the genotype but rather the interaction between the genotype and the environment in which the organism exists. The expression of these traits are observable in an organism. The expression of such observable traits is called as phenotype.