mudsill

The lowest sill, block, or timber supporting a building, located at or below ground level.

Specifically, the bed-piece or bottom timber of a dam placed across the stream and usually resting on rocks or in mud.

The lowest sill of a structure, resting on the ground.

A lowborn, ignorant, contemptible person.

The lowest sill of a structure, usually embedded in the soil; the lowest timber of a house; also, that sill or timber of a bridge which is laid at the bottom of the water. See sill.