In Chinese usage, the cuckold (or wittol) is said to be “戴綠帽子” dài lǜmàozi, translated into English as ‘wearing the green hat’. The term is an allusion to the sumptuary laws used from the 13th to the 18th centuries that required males in households with prostitutes to wrap their heads in a green scarf (or later a hat).
In church heraldry, Bishops and Archbishops use use a green hat. Up until the last decade, the Chinese Bishops and Archbishops used other colors for this very reason.