door sill; threshold plate
Refers to the bottom horizontal part of a door frame, often a raised strip or plate that the door closes against. A somewhat specialized architectural term.
The door sill at the entrance was getting worn, so I replaced it with a new one.
Standard kanji spelling using 靴 (shoe).
Variant using 沓, an older or less common character for shoe.
Compound of 靴 (shoe) and 摺り (rubbing, scraping), literally 'shoe rubbing', referring to the part of a door frame that shoes scrape against.