Cao is romanized as "Tsao" in Wade-Giles (Ts'ao), which is widely adopted in Taiwan, although the apostrophe is often omitted in practice.
[3] It originated from the Zhou-era Duchy of Cao founded by Zhenduo [zh].
The later claim that Cao is said to have been descended from the Yellow Emperor via the Zhuanxu Emperor should not be confused with the Chinese surname Gao or the Vietnamese surname Cao.
[4] Cao can also serve as the romanization for the Chinese surnames Cāo (操), Cǎo (草), and Cào (鄵) as well; however, they are not nearly so common.
Its modern use as a curse word depends on a recent homophone and is unrelated to the surname.