This word is made up of two other words, their combination manage to convey a positive feeling. The first part of the word (Zukunft-) means “future”, the second part (-musik) means “music”. The two words put together mean “music of the future” (Zukunftsmusik)*. There is no Spanish or English word to translate Zukunftsmusik directly but you can understand its meaning by observing its use. This word is being used to describe plans or facts that could happen or that we want to happen in the future. Those things may happen but their materialization is still pretty far or subject to uncertainty. It is not a word to describe fantasies, hypothesis or things that we already regard as impossible, it is a word to emphasize that the future that we hope does not necessarily answer to our wishes: things may happen as we imagine or not. For instance: When I am a famous writer I am going to donate all my money to projects related to social inclusion, but this is “music of the future”. One may say that this word suggests that our dreamed future is “music to our ears”.
*The letter “s” serves to connect the two words in this case.