Top cave radical (Kangxi #116) — a dwelling-pit roofed by
宀 with two leg-strokes for the opening, picturing an underground chamber. Indexes
窖 in the dug-hole family:
穿 (pierce),
窝 (nest),
窜 (flee into a hole),
穷 (impoverished). A
窖 is a storage pit dug into the earth, often for pickling vegetables or root crops.