haploid
adj. describing a nucleus, cell, or organism that possesses only one representative of each chromosome, as in a sperm or egg cell. In most organisms, including humans, fusion of the haploid sex cells following fertilization restores the normal diploid condition of body cells, in which the chromosomes occur in pairs. Hence for humans, the haploid number is 23 chromosomes, which is half the full complement of 46 chromosomes.