What is the difference between homozygous and heterozygous?

Homozygous means there are two copies of the same allele present at a specific locus (position) on a chromosome, e.g. two copies of the allele for blue eyes. Whereas, heterozygous means there are two copies of different of different alleles present at a specific locus on a chromosome, e.g. one copy of the allele for blue eyes and one copy of the allele for brown eyes. Remember Homo = the same, Hetero = different.