Diphda, also known as Deneb Kaitos, is a bright star in the constellation Cetus. While there may not be many exact synonyms for the word "diphda," there are several related terms that may be useful in describing it or other celestial objects. For example, words like "astral," "celestial," or "stellar" all refer to things related to the stars or the study of astronomy. "Luminous" or "radiant" may be used to describe the brightness or energy emitted by celestial objects, while "cosmic" or "galactic" suggest a sense of vastness or grandeur. Overall, the many synonyms and related terms associated with diphda reflect the awe-inspiring beauty and mystery of the celestial realm.