The vast majority of them were officially named after geographical locations, but since the organisation of the camps changed frequently, you might come across several names for the same (sub-)camp. The SS also used code names for some of the camps it wanted secret (a good example is the Mittelbau concentration camp where missiles were produced). Those names were sometimes pretty arbitrary (e. g. Kommando 48a for Niedergebra) or only used within local units. Some camps were known by several thematically similar code names somewhat related to the camp (e.g. Ebensee was referred to as Kalk (limestone), Kalksteinbergwerk (limestone mine), Solvay and Zement (cement)).

However, there was actually a naming system in place (or several, actually). The Ministry of Armaments and Ammunition had a system that was specific to secret projects rather than concentration camps, meaning that the concentration camp would only get that code name if it housed secret projects like the missile factory at Mittelbau. There's a list on German Wiki and it mostly involves animals and plants and given names.