nucleotide
a nucleoside in which the sugar carries at least one phosphate group; nucleotides are the subunits that make up nucleic acid.
Description: Unit building block of DNA. It consists of a sugar and phosphate backbone with a base attached.Source: Specialized encyclopedia and dictionariesDescription: A compound made up of these three components: a sugar, phosphate and a nitrogen-containing base. Found as individual molecules (e.g., ATP, the «energy molecule»), or as many nucleotides linked together in a chain (nucleic acid such as DNA).Source: Specialized encyclopedia and dictionaries
defined: One of the structural components, or building blocks, of DNA and RNA. A nucleotide consists of a base (one of four chemicals: adenine, thymine, guanine, and cytosine) plus a molecule of sugar and one of phosphoric acid.
explained:
Listen to a detailed explanation. Dr. Robert Nussbaum, of the National Human Genome Research Institute's Laboratory of Genetic Disease Research, defines nucleotide.
illustrated: 
View illustration related terms: 
base pair,
deoxyribonucleic acid (DNA),
genetic code (ATGC),
ribonucleic acid (RNA)
The monomeric unit that makes up the DNA or RNA, formed by a phosphate group, a pentose and one of the nitrogenous bases (A, T/U, C, G). Nucleotides in RNA are adenylate, guanylate, cytidylate and uridylate; in DNA, they are (d)adenylate, (d)guanylate, (d)cytidylate and thymidylate.