Final answer:
A diploid cell or organism has two copies of every chromosome, consisting of one set from each parent. These cells have homologous chromosomes with genes that can have different alleles, leading to variation in inherited traits.
Step-by-step explanation:
The term diploid means that a cell or organism has two copies of every chromosome. In the context of somatic cells, which are any cells that are not reproductive cells, diploid cells contain two sets of chromosomes; one set inherited from the mother and one set from the father. These chromosomes are called homologous chromosomes and although they are matched pairs containing the same genes, they can have different alleles, which are variations of these genes.
Diploid organisms are the norm for most animals and plants, contrasting with haploid cells that contain only one set of chromosomes and are typically found in reproductive cells like sperm and eggs. When discussing inheritance, like that of flower color in plants, diploid organisms have two genetic copies of a given gene which may express different traits due to having different alleles.