There are no commonly used synonyms for the word "rhykenologist," as it is a relatively obscure term. For those unfamiliar with the word, a rhykenologist is someone who studies old and rare books. While there may not be any exact synonyms for this term, related terms may include bibliophile (a lover of books), book collector, or book historian. Additionally, someone who specializes in the preservation and restoration of books may be referred to as a book conservator. Regardless of the specific term used, those who have a love for old and rare books share a passion for preserving and understanding the history they hold.