Chromosome

A chromosome is one of the threadlike "packages" of genes and other DNA in the nucleus of a cell.

Different kinds of organisms have different numbers of chromosomes. Humans have 23 pairs of chromosomes, 46 in all: 44 autosomes and two sex chromosomes. Each parent contributes one chromosome to each pair, so children get half of their chromosomes from their mothers and half from their fathers.

Sources:  image from the National Human Genome Research Institute (NHGRI) Genetic Illustrations; definition from the National Human Genome Research Institute (NHGRI) Glossary of Genetic Terms