Nucleoside Reverse Transcriptase Inhibitors make up what's called the "backbone" of every traditional HAART regimen. It is also an awfully long phrase to type, so I will refer to them only as "NRTIs" from here on out.
But before I go on, there's another distinction I have to make. There are actually both nucleoside and nucelotide reverse transcriptase inhibitors. We lump them into the same "NRTI" bucket because they work in exactly the same way. But they are technically different from each other.