soap-box (n.)youdaoicibaDictYouDict[soap-box 词源字典]
also soapbox, 1650s, "box for holding soap," later especially a wooden crate in which soap may be packed; from soap (n.) + box (n.). Typical of a makeshift stand for a public orator since at least 1907. Also used by children to make racing carts, as in soap-box derby, annual race in Dayton, Ohio, which dates to 1933.[soap-box etymology, soap-box origin, 英语词源]