RDGE is a four-letter word that has multiple synonyms based on its different meanings. If we look at its geological meaning, it refers to a narrow, elongated elevation of land. In this case, the synonyms for RDGE could be crest, hilltop, mountain range, peak, ridge line, or summit. On the other hand, RDGE is also a commonly used acronym for Registered Dental Hygienist Examination. For this meaning, synonyms may include dental hygiene test, dental hygiene licensure exam, or dental hygiene national board exam. In summary, the synonyms of RDGE are highly dependent on the context and meaning of the word.