The term for when an organism has two identical alleles for a trait is homozygous.

Here's a breakdown:

* Allele: A variant form of a gene.

* Homozygous: Having two identical alleles for a particular trait.

* Heterozygous: Having two different alleles for a particular trait.

For example, if an individual has two alleles for eye color, both of which are brown, they are homozygous for brown eyes.