A for adenine, G for guanine), the second letter indicates the number of phosphates (mono, di, tri), and the third letter is P, standing for phosphate. The first letter indicates the identity of the nitrogenous base (e.g. Nucleotides are commonly abbreviated with 3 letters (4 or 5 in case of deoxy- or dideoxy-nucleotides). Thus, nucleoside triphosphates are a type of nucleotide. To provide information about the number of phosphates, nucleotides may instead be referred to as nucleoside (mono, di, or tri) phosphates. Nucleotides are nucleosides covalently linked to one or more phosphate groups. The term nucleoside refers to a nitrogenous base linked to a 5-carbon sugar (either ribose or deoxyribose). For example, azidothymidine (AZT) is a nucleoside analogue used to prevent and treat HIV/AIDS. Nucleoside analogues may also be used to treat viral infections. Synthesis pathways differ depending on the specific nucleoside triphosphate being made, but given the many important roles of nucleoside triphosphates, synthesis is tightly regulated in all cases. Nucleoside triphosphates cannot be absorbed well, so they are typically synthesized within the cell. Nucleoside triphosphates also serve as a source of energy for cellular reactions and are involved in signalling pathways.

They are the molecular precursors of both DNA and RNA, which are chains of nucleotides made through the processes of DNA replication and transcription. A nucleoside triphosphate is a nucleoside containing a nitrogenous base bound to a 5-carbon sugar (either ribose or deoxyribose), with three phosphate groups bound to the sugar.

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