Double daggers are a type of punctuation mark used to indicate a footnote or cross-reference in printed material. They are also known by several other names, including "obelisks," "obelus," or simply "dagger" or "double dagger." Some common synonyms for the double dagger symbol include the "obelisk", "obelus", "obelos", "obeloi", and "obelisci". However, the exact term used may vary depending on the context or location. Nonetheless, using any of these synonyms will help convey the intended meaning and also add variation to one's writing.