Longman Dictionary of Contemporary English
The Collaborative International Dictionary
nucleic acid \nu*cle"ic ac"id\ (n[=oo]*kl[=a]"[i^]k [a^]s"[i^]d or n[=oo]*kl[=e]"[i^]k), n. (Chem., Biochem., Genetics) A natural or synthetic polymer consisting of chains of ribonucleotide or deoxyribonucleotide units.
Note: The nucleic acids are vital constituents of all living cells, carrying the genetic information propagated between generations, and, while a cell is alive, having a continued function in coding for the amino acid sequence of proteins being synthesized by the cell. The two natural types of nucleic adic are ribonucleic acid (RNA) and deoxyribonucleic acid (DNA).
Wiktionary
n. (context biochemistry genetics English) 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
WordNet
n. (biochemistry) any of various macromolecules composed of nucleotid chains that are vital constituents of all living cells
Wikipedia
Nucleic acids are biopolymers, or large biomolecules, essential for all known forms of life. Nucleic acids, which include DNA (deoxyribonucleic acid) and RNA (ribonucleic acid), are made from monomers known as nucleotides. Each nucleotide has three components: a 5-carbon sugar, a phosphate group, and a nitrogenous base. If the sugar is deoxyribose, the polymer is DNA. If the sugar is ribose, the polymer is RNA. When all three components are combined, they form a nucleic acid. Nucleotides are also known as phosphate nucleotides.
Nucleic acids are among the most important biological macromolecules (others being amino acids-proteins, sugars-carbohydrates, and lipids-fats). They are found in abundance in all living things, where they function in encoding, transmitting and expressing genetic information. In other words, information is conveyed through the nucleic acid sequence, or the order of nucleotides within a DNA or RNA molecule. Strings of nucleotides strung together in a specific sequence are the mechanism for storing and transmitting hereditary, or genetic information via protein synthesis.