noun
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.
玄関の靴摺りが傷んできたので、新しいものに交換した。
The door sill at the entrance was getting worn, so I replaced it with a new one.
敷居 is the general term for a threshold or sill, often used in everyday contexts. 靴摺り is more specific to the bottom plate of a door frame, sometimes with a connotation of a shoe-scraping strip.
Compound of 靴 (shoe) and 摺り (rubbing, scraping), literally 'shoe rubbing', referring to the part of a door frame that shoes scrape against.