ユコウMeanings1nounyukou; Japanese citrus varietyusually written using kana aloneA specific Japanese citrus fruit (Citrus yuko). The name is usually written in katakana.ユコウは日本にほん原げん産さんの柑かん橘きつ類るいの一いっ種しゅです。Yukou is a type of citrus fruit native to Japan.