GO:0006308:   DNA catabolic process
The cellular DNA metabolic process resulting in the breakdown of DNA, deoxyribonucleic acid, one of the two main types of nucleic acid, consisting of a long unbranched macromolecule formed from one or two strands of linked deoxyribonucleotides, the 3"-phosphate group of each constituent deoxyribonucleotide being joined in 3",5"-phosphodiester linkage to the 5"-hydroxyl group of the deoxyribose moiety of the next one.