
1) Footplate
Found on
https://www.crosswordclues.com/clue/mudsill

• (n.) 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. • (n.) Fig.: A person of the lowest stratum of society; -- a term of opprobrium or contempt.
Found on
http://thinkexist.com/dictionary/meaning/mudsill/

A wood foundation member, usually a pressure treated 2x4 or 2x6, bolted to the foundation and on which other framing members can be attached.
Found on
http://www.encyclo.co.uk/local/20933
Mud'sill` noun Fig.: A person of the lowest stratum of society; -- a term of opprobrium or contempt. [ Southern U. S.]
Found on
http://www.encyclo.co.uk/webster/M/111

- Bottom horizontal member of an exterior wall frame which rests on top a foundation, sometimes called sill plate. Also sole plate, bottom member of interior wall frame.
Found on
http://www.homebuildingmanual.com/Glossary.htm

Bottom horizontal member of an exterior wall frame which rests on top a foundation, sometimes called
Found on
https://www.encyclo.co.uk/local/22400

Bottom horizontal member of an exterior wall frame which rests on top a foundation, sometimes called sill plate. Also sole plate, bottom member of interior wall frame.
Found on
https://www.homebuildingmanual.com/Glossary.htm

the lowest sill of a structure, usually placed in or on the ground. Also called
Found on
https://www.infoplease.com/dictionary/mudsill
No exact match found.