frottoir
n.— «Zydeco, like Simien, is a native of the southwest region of Louisiana. It’s the music of the prairies and swamps. The primary instruments are the accordion and the frottoir, which is a rubboard.» —“Blues, Creole, Cajun and zydeco” by Molly Tarantino Richmond Times-Dispatch (Va.) Oct. 13, 2005. (source: Double-Tongued Dictionary)