umbrella frame; umbrella ribs
Refers to the structural skeleton of an umbrella, including the ribs and stretchers.
強風で傘骨が折れてしまった。
The umbrella frame broke in the strong wind.
Compound of 傘 (kasa, 'umbrella') and 骨 (hone, 'bone'), with rendaku voicing of ほね to ぼね.