- The constituent purine or pyrimidine bases of DNA or RNA with their corresponding deoxyribose or ribose sugars.
Definition from: NCI Thesaurus via Unified Medical Language System at the National Library of Medicine
- A compound (as guanosine or adenosine) that consists of a purine or pyrimidine base combined with deoxyribose or ribose and is found especially in DNA or RNA.
Definition from: Merriam-Webster's Medical Dictionary by Merriam-Webster Inc.
See also Understanding Medical Terminology.