The name is said to come from the fact that it was made from simple material that was stretched using only water with no starch or, according to the "Zoku Shinsho Hisho" (book about names of costumes and memos of the Emperor's clothes), because it was convenient for both clear and rainy weather, but anyway, it seems to have been so named because it was a simple garment.
名称は糊を付けず水をつけて張った簡素な生地を用いるからとも、晴雨両用に便利なため（『続深窓秘抄』）ともいうが、いずれにせよ簡素な服飾であることからの命名のようである。