bowl
埦 centers on a bowl: a small, open container, typically made of earth or clay, used for holding food or other items.
埦 combines 土 (earth, clay) with 宛, which likely contributes the sound ワン. The character likely originally referred to an earthenware bowl.
The left side 土 (earth) suggests clay, and the right side 宛 looks like a container with a lid. Picture shaping clay into a small bowl.
For ワン, imagine a one-of-a-kind clay bowl: one -> ワン, and the bowl is made of earth.