We don't have synonyms for nucleosides yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are nucleoside, nucleotides and nucleotide.
(n) :
(biochemistry) an organic molecule in which a nitrogenous heterocyclic base (or 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.
(n) :
(biochemistry) an organic molecule in which a nitrogenous heterocyclic base (or 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.