"cover" radical in Chinese characters (Kangxi radical 14), occurring in 軍|军[jun1], 冠[guan1] etc, known as 禿寶蓋|秃宝盖[tu1 bao3 gai4] or 平寶蓋|平宝盖[ping2 bao3 gai4]
lit. to sleep on brushwood and taste gall (like King Gou Jian of Yue 勾踐|勾践[Gou1 Jian4]), in order to recall one's humiliations) (idiom) / fig. to maintain one's resolve for revenge