nucleobase

https://doi.org/10.1351/goldbook.09710
Purine or pyrimidine nitrogenous base occurring in deoxyribonucleic acid (DNA) or ribonucleic acid (RNA).
Example: Purine and pyrimidine bases of ribo- and deoxyribonucleotides.
Source:
PAC, 2018, 90, 1121. (Terminology of bioanalytical methods (IUPAC Recommendations 2018)) on page 1148 [Terms] [Paper]