"roof" radical (Kangxi radical 40), occurring in 家, 定, 安 etc, referred to as 寶蓋|宝盖[bao3 gai4]
宀
=
丶
+
冖
:
Mnemonic symbol: the strokes of this character look like a graduation cap (宀).
Marilyn Monroe (mi-) wants to cook in the anthill's kitchen (an2) but she's afraid of the ants. That's why she builds a bunker: she uses a saucepan lid (冖) as the base, constructs pillars out of petals (丶) and uses a graduation cap (宀) as the roof.