A genotype refers to the specific genetic makeup of an organism, represented by the alleles inherited from its parents. It determines various traits, such as eye color or height, and is often denoted using letters, like AA, Aa, or aa, where each letter represents a different allele. Genotypes can be classified as homozygous, where both alleles are the same (e.g., AA or aa), or heterozygous, where the alleles are different (e.g., Aa). Understanding genotypes is essential in fields like genetics, agriculture, and medicine, as they influence how traits are expressed in organisms.