kāi cáo

1. 溝を付ける．溝を掘る
2. スロット、溝切り

kāi cáo shì

〈修正歓迎〉溝付型

〈車〉slotted oil control ring

〈車〉slotted nut

〈車〉hezagon castle(slotted)nut

〈車〉slotted round nut

〈車〉slotted round head screw

〈車〉slotted cheese-head screw