Isochronism refers to the state of having the same duration or frequency. There are a few synonyms for this word that may be useful in different contexts. Some of these words include synchronicity, simultaneity, coetaneousness, and concurrence. Synchronicity is when things happen at the same time, whereas simultaneity refers to the state of occurring simultaneously. Coetaneousness means having the same age, and concurrence is when two or more events happen at the same time. These words can be useful in various fields, such as science, mathematics, and music, where isochronism plays a critical role. By using these synonyms, individuals can create diverse and meaningful expressions in their communication.