If you mean the short names that given to cabin crew members before each flight, such as “3L”, “R4”, “1L”, etc. then these are their positions.
These positions are assigned before every flight (or series of flights done by the same crew in the same aircraft), these are the positions in each aircraft. Each flight attendant will be responsible for a specific zone (usually regarding safety and security, could be service as well).
The common positions are Rn and Ln, or nL and nR depending on the airlines. For example, 1L or L1 means door 1 left, this means that this cabin crew member is responsible for the door 1 left and the zone this door serves. R3 means door 3 right and so on.
There are other positions as well, it depends on the aircraft type and/or airlines. For example the X positions, such as R4X, which is the crew member responsible for the aft right galley next to R4 door. You can also find R1X and so on. The X position usually refers to a person responsible for a galley, not a door. Again, this can be different from one airline to another.
For aircraft with upper decks (747), the positions would be UDL, UDR, etc. Those stand for "upper deck left, upper deck right", you can also find a UDG, which is the member covering the upper deck's galley. Not sure about names in A380, but it must be something close to that.
Some other aircraft have different names, such as the MD90, you can find a T position, which stands for tail, as the crew member at the back is at the center.
For the cabin manager or purser, almost each airline has a different name: Cabin manager, purser, senior, supervisor, cabin chief, etc. Sometimes just an abbreviation (CCIC), or cabin crew in command or something like that.
It is also more professional to use these codes in announcements like “R3 to aft galley” rather than saying names.