Describes a cell or organism which has more than the normal total number of chromosomes. For example, humans normally have 46 chromosomes per cell - but if a human individual has 47 or more chromosomes per cell, then that person is hyperploid. Hyperploidy is the opposite of hypoploidy.
From the BioTech Dictionary at http://biotech.icmb.utexas.edu/. For further information see the BioTech homenode.