Chiliadal is a rarely used word that refers to a period of 1000 years. However, there are several synonyms available for this word that are often used in everyday language. Some of the common synonyms for chiliadal include millennium, grand millennium, and age. These words are often used in a broader context to describe a long period of time, typically a thousand years or more. Other synonyms of chiliadal include eon, era, epoch, and cycle. These words represent long spans of time and are typically used in scientific or historical contexts. Whatever the word used, the significance of a chiliadal or a millennium cannot be understated, representing a long period of growth and change over time.