The name "nucleic acid" comes from the fact that they were first described because they actually had acidic properties, much like the acids that you know. And the nucleic part comes from the fact that they were first isolated because they were found in the nucleus.
A nucleic acid is a polymeric macromolecule made up of repeated units of monomeric 'nucleotides' composed of a nitrogenous heterocyclic base which is either a purine or a pyrimidine, a pentose (five carbon) sugar (either ribose or 2′-deoxyribose), and one to three phosphate groups.
The term nucleic acid is the overall name for DNA and RNA, members of a family of biopolymers, and is synonymous with polynucleotide. Nucleic acids were named for their initial discovery within the nucleus, and for the presence of phosphate groups (related to phosphoric acid).
