Haploid is the term used when a cell has only one set of chromosomes. A normal eukaryote organism is composed of diploid cells, one set of chromosomes from each parent. However, after meiosis, the number of chromosomes in gametes is halved. That is the haploid condition.
In humans, the diploid number of chromosomes is 46 (2x23). The number in haploid cells (sperm and eggs) is 23. Some whole groups of animals are haploid, such as male hymenoptera (ants, bees and wasps).