Isochroous is a technical term used mostly in physics and music to describe things that are of the same pitch or frequency. However, if you want to make your writing more engaging and varied, you might want to consider using some synonyms instead of the word isochroous. Some of the synonyms you could use instead of isochroous include equidistant, even-paced, synchronous, simultaneous, harmonious, and regular. Each of these words carries a slightly different connotation, but they all describe things that are of the same pitch or tone and would be suitable alternatives to isochroous in certain contexts.