Let’s begin at the beginning…
First there was the NAP160 and NAP200 (which become the NAP250). Taking the NAP160 as an example, NAP = Naim Audio Poweramp. 160 is the combined power output of L+R channels into a 4 ohm load (80w/channel into 4 ohms).
Then there was the NAC12. NAC = Naim Audio Control. The first number (1) indicates it was the first pre-amp designed by Naim, and the second number refers to the number of channels, 2. After this followed the NAC22, NAC32, NAC42, NAC52, NAC62, NAC72, NAC82, NAC92 and NAC102. IN the case of the NAC52, it actually was released after the NAC62 and NAC72 as it took so long to develop.
When the range was updated to the current Classic/Reference look, the old NAC102, 82, and 52, became the NAC202, 282, and 252. In addition a pre-amp above and beyond the NAC52 was developed, called the NAC552.
As for the pre-amp power supplies, first came the NAPS (Naim Audio Power Supply), then the SNAPS (Super Naim Audio Power Supply), then the HICAP (High capacity), Then Supercap (Super capacity), and Flatcap (some humour - a small PSU in a slimline - flat - case).
NAIT - Naim Audio InTegrated. This pretty straightforward, NAITs 1, 2, 3 and 5 were introduced between 1983 and 2000. Then a back to basics lower cost NAIT was introduced called the NAIT 5i, which went through a couple of iterations and still exists in latest form as the NAIT 5Si. The NAIT XS/XS2/XS3 was more of a continuation from where the old NAIT 5 left off. The Supernait a higher level integrated with more power at greater cost. Currenty in its third iteration as the Supernait 3.
CD players are pretty straightforward; First there was the CDS with CDPS power supply. Then an integrated version called the CDI. Then a slimline 3 series version called the CD3 (matched the look of the NAIT 3). CDS, became CDS2 (with XPS), and then CDS3 (with XPS2). CDI became CD2, then CDX, then CDX2. CD3 became CD3.5, then CD5, CD5x, CD5xs. At the same time as the NAIT 5i, a less expensive CD player was introduced at a lower cost to match, called the CD5i. Current version is the CD5Si. There was also a 500 series top end player introduced above the CDS3, called the CD555 and powered by the 555PS, which happily could also be used in place of an XPS on other appropriate players.
There’s more of course (have a read through the forum FAQ for info on SNAICs DINs etc…), but that’s the basic foundation.