Seiketsu (清潔) doesn't mean standardize; it means "clean, hygienic, sanitary". You hear it in the negative: fuseiketsu means filthy. The first four S's are all

Seiketsu (清潔) doesn't mean standardize; it means "clean, hygienic, sanitary". You hear it in the negative: fuseiketsu means filthy. The first four S's are all in the same semantic neighborhood: they all have to do with neatness, cleanliness and order. Basically they collapse into one. The last S, shitsuke, is just discipline. "Be clean/neat/tidy, and have discipline". Yay ...