Radical
Hill

Mnemonic

Two layers of earth stacked on top of each other — that's exactly what forms a hill! The bottom earth is the wide, sturdy base, and the top earth is the rounded peak. Whenever you see earth piled upon earth, nature is sculpting a hill right before your eyes.
Additional thoughts
Visualize shoveling one mound of earth on top of another, watching the ground rise into a gentle hill. Two earth radicals = double the dirt = elevated terrain.
Quick recall
Earth piled on earth rises into a hill.