The term is a mess in computer science. The standalone definition almost works reverse to the definition in thermodynamics. There is also entropy coding, which

The term is a mess in computer science. The standalone definition almost works reverse to the definition in thermodynamics. There is also entropy coding, which is a compression through a set of prefixes and entropy compression which is about the termination of processes. I am sure there are many more... Most practical approach is to read the meaning through the respective context and sometimes to ignore the sign... That said, I believe the parent is correct. Compressed data certainly has a higher entropy. But any additional bit from an image or sound is rarely independent in the first place like Shannon demanded it to be the case for the definition of entropy. That they are not independent is precisely the attack vector of many forms of compression. For example the base frequency of a JPG has more entropy if we use the literal definition than higher frequencies that get removed because they lack entropy in a information technical sense.