Roundels can be described using a variety of synonyms that convey their unique shape and purpose. One common synonym for roundels is "circles," as they are typically circular in shape and used as markers or insignia. Another term frequently used to describe roundels is "discs," which refers to their flat, round shape that is often used in decorative or functional applications. "Medallions" is another synonym for roundels, as they are often used as ornamental pieces in architecture or design. Other possible synonyms include "tokens," "plaques," and "emblems," all of which convey the idea of a distinctive round shape that serves a specific purpose or meaning.