Definition: HapMap (short for "haplotype map") is the nickname of the International HapMap Project, an international project that seeks to relate variations in human DNA sequences with genes associated with health. A haplotype is a set of DNA variations, or polymorphisms, that tend to be inherited together. A haplotype can refer to a combination of alleles or to a set of single nucleotide polymorphisms (SNPs) found on the same chromosome. The HapMap describes common patterns of genetic variation among people.
Source: National Human Genome Research Institute's Talking Glossary of Genetic Terms