Here's a breakdown:

* Heterozygote: An individual with two different alleles for a particular trait.

* Dominant allele: An allele that exerts its effect even when paired with a recessive allele.

* Recessive allele: An allele whose effect is masked by the dominant allele.

In simpler terms, if you have one dominant allele and one recessive allele, the dominant allele will "win" and determine the trait you express.

For example, let's consider eye color:

* Brown eyes (B) are dominant over blue eyes (b).

* A person with the genotype Bb (one dominant brown allele and one recessive blue allele) will have brown eyes because the brown allele is dominant.