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ridge (of roof)
back of a sword
counter for buildings, apartments, etc.
「棟」 has another reading with different meanings.
屋根の棟が台風で壊れてしまった。
The ridgepole of the roof was damaged by the typhoon.
棟の修理に専門の職人を呼んだ。
I called a craftsman to repair the ridgepole.
この家の棟は百年前のものだ。
This house's ridgepole is from a hundred years ago.