/n(y)o͞oˈklē-ik/
Noun, pl. nucleic acids
1. A complex organic substance present in living cells, especially DNA or RNA, whose molecules consist of many nucleotides linked in a long chain. (Google Dictionary)
2. Any of the group of complex compounds consisting of linear chains of monomeric nucleotides whereby each monomeric unit is composed of phosphoric acid, sugar and nitrogenous base, and involved in the preservation, replication, and expression of hereditary information in every living cell.(www.biology-online.org)
3. (Biochemistry, Genetics)
Any acidic, chainlike biological macromolecule consisting of multiply repeat units of phosphoric acid, sugar and purine and pyrimidine bases; they are involved in the preservation, replication and expression of hereditary information in every living cell. (Wiktionary.org)
4. Nucleic acids are large biological molecules essential for all known forms of life. They include DNA (deoxyribonucleic acid) and RNA (ribonucleic acid). Together with proteins, nucleic acids are the most important biological macromolecules; each is found in abundance in all living things, where they function in encoding, transmitting and expressing genetic information. (Wikipedia.org)