Time crystals are like Folger's Crystals, wherein when all objective reality is removed from our existence, what is left are the Time Crystals. Time Crystals can be brewed into a bitter murky brown/black drink, which is how you know it's from our universe. Time Crystals are the distilled essence of communism.

They had to be called something, and the unique property of the system being in a perpetual state of quantum oscillation without loss of energy, which in turn means they don't possess one of the fundamental properties we associate with normal matter, that is, kinetic energy in the classical non-relativistic sense, seems to lend itself to an equally exotic nomenclature.

In classical physics, time is simply another state of matter: there's length, width and height (the classic "three dimensions") with time being a measurement of duration. If you think of it as a three dimensional object moving through space-time, the "time" portion represents the duration of the object moving through space, which can be measured just like the other three.

But, time crystals don't obey these same laws, because they work at a completely different level: they move without loss of energy, so there's no entropy as there would be in the classical model; thus they can exist perpetually in the same state of oscillation for essentially infinity - and infinity, as we all know, is the ultimate measurement of time.