What is the full form of dBc?

Could you please clarify the full form of dBc for me? I've encountered this term in various discussions related to cryptography, telecommunications, and even in some financial contexts, but I'm not entirely sure of its exact meaning. I understand it's related to some sort of decibel measurement, but I'm curious about the specific context and what the 'c' stands for. Is it a standard abbreviation for a certain technical concept? Or is it perhaps a shorthand for a more complex phrase? I'd appreciate any insight you could provide on this matter.