| 1 | Middle English | schalen | — |
| 2 | Middle English | schale | shell, husk; scale |
| 3 | Old English | sċealu | shell, husk; shell, husk, pod; husk |
| 4 | Proto-West Germanic | *skalu | — |
| 5 | Proto-Germanic | skalō | shell; lump, ball |
| 6 | Proto-Indo-European | (s)kelH- | to cut; to split, to separate |
| 7 | Proto-Indo-European | (s)kel- | to bend, crook; bent, crooked; leg, heel, knee,... |