What does 48k mean when pertaining to a PIC?
Many PIC microcontrollers have instructions which are 12 or 14 bits long, and use word addresses to identify the locations of instructions.  Especially with devices which can't do anything with the code storage area except execute instructions from it, describing the capacity of a part as "8192 14-bit instructions" is more helpful than describing it as holding "14,336 bytes".

While many PIC parts use 16-bit instructions and have the ability to access code storage as a sequence of octets, describing the capacity of some parts in instruction-sized units and the capacity of others in octets would be confusing.  When comparing the code size limits for parts where code storage is or is not byte-addressable, it's more helpful to describe the sizes of both in terms of instructions.