any of various compounds consisting of a purine or pyrimidine base linked to a carbohydrate: a major component of a nucleotide
Origin of nucleosidefrom nucleo- + -ose + -ide
Any of various compounds, such as adenosine or guanosine, that consist of a sugar, usually ribose or deoxyribose, linked to a purine or pyrimidine base. Nucleosides are constituents of the nucleotides that make up nucleic acids.
- (biochemistry) an organic molecule in which a nitrogenous heterocyclic base (nucleobase), which can be either a double-ringed purine or a single-ringed pyrimidine, is covalently attached to a five-carbon pentose sugar (deoxyribose in DNA or ribose in RNA). When the phosphate group is covalently attached to the pentose sugar, it forms a nucleotide.