The phrase "is tune" refers to something being in harmony or alignment. Synonyms for this can include: is in sync, is on track, is on point, is accurate, is consistent, is in agreement, is in rapport, and is in conformity. In music, "is tune" refers specifically to a song or melody that is well-orchestrated and pleasant to listen to. Related synonyms for this can include: is melodic, is rhythmic, is harmonious, is melodious, is sweet-sounding, and is tuneful. Overall, there are many different ways to say "is tune" depending on the context and the specific meaning that is intended.