一切經音義 9.240

9.240

匳底（今作[簽*ㄆ]同力占反蒼頡篇盛鏡器曰匳謂方底者也）。

匳底 (now written as 𪚑, the same, fanqie: 力 + 占. The Cangjiepian says: 'A receptacle holding a mirror is called a 匳', referring to one with a square base).