An allele is a viable DNA (deoxyribonucleic acid) coding that occupies a given locus (position) on a chromosome.
Homozygous is a genetic condition where an individual inherits the same alleles for a particular gene from both parents.
heterozygous refers to a pair of genes where one is dominant and one is recessive — they're different.
genotype is the genetic makeup of a cell, an
organism, or an individual usually with reference to a specific
characteristic under consideration.
A phenotype is the composite of an organism's
observable characteristics or traits, such as its morphology,
development, biochemical or physiological properties, phenology,
behavior, and products of behavior (such as a bird's nest).
Punnett square is a diagram that is used to predict an outcome of a particular cross or breeding experiment.