Refers to the grooved track or rail on which a sliding door (such as a 障子 or 襖) slides. A somewhat specialized architectural term.
In old houses, the door runner can wear down, making the sliding door hard to open and close.
tree wax; insect wax; Chinese wax
A type of wax obtained from certain trees or insects, historically used in East Asia. The cross-reference to 水蝋蝋 (いぼたろう) suggests a specific traditional wax. Rare and technical.
See also: いぼたろう
The wax called 戸走り was once used for candles and medicinal products.
The derivation is uncertain. The kanji 戸 (door) and 走り (running) suggest the sliding-door sense, while the wax sense may be a separate homophone or a specialized extension.