What is the term for having multiple sets of the haploid number of chromosomes?

The term for having multiple sets of the haploid number of chromosomes is euploidy. Euploid organisms have complete sets of chromosomes that are normally found in the species, such as diploids (two sets), triploids (three sets), and tetraploids (four sets). When referring to multiple sets, the defining characteristic is that these sets are whole multiples of the haploid number, which distinguishes euploidy from conditions like aneuploidy, where there is an abnormal number of chromosomes.

In contrast, diploidy specifically refers to having two sets of chromosomes, while haploidy means having only one set of chromosomes. Triploidy, while indicating three sets of chromosomes, is a specific case of euploidy. Therefore, euploidy serves as the overarching term that includes both diploidy and triploidy, making it the most accurate choice for indicating multiple sets of the haploid number.