The word "picas" has a few synonyms that are often used interchangeably. One synonym is "points," which refers to a typographic unit of measurement that is used to determine the size of type. Another common synonym is "didots," which are named after the French printer and engraver Firmin Didot and are also a unit of typographic measurement. Additionally, "ems" is another synonym for "picas," as it is also a typographic measurement unit. These synonyms are typically used in the context of typography and printing, and all serve the same purpose of helping to determine the layout and design of printed material.